The relieving force consisted of a mixture of units, hastily assembled: The 7th (Meerut) Division under Major-General Sir George Younghusband (right), newly arrived from France; two additional Brigades, a Brigade of Cavalry and various engineers and other units. In total, it added up to some 19000 troops, under the overall command of Lieut-Gen. Sir Fenton Aylmer. This collection took the title of the Tigris Corps.

The Turkish Army had established a camp at Sheikh Sa'ad, which later turned out to be merely an outpost of a much larger force - five Turkish Divisions, amounting to 22500 men. The camp held some 4000.

Aylmer ordered the 7th (Meerut) Division and the Cavalry Brigade - supported on the river by a small number of gunboats - forward towards Sheikh Sa'ad on the 3 January 1916. Signals came from Kut saying that large numbers of Turkish troops had been seen moving downstream, making straight for the same objective. An aircraft spotted the Turks entrenching on both sides of the river, in front of Sheikh Sa'ad with the British force now only 10 miles distant. While Younghusband was all for an immedaite assault, Aylmer ordered him to hold fast, and for the 12th Indian Division under George Gorringe to make an advance from Nasiriyeh to divert attention. This action made no difference; the Turks were not deceived.

Urged on by Townshend in Kut and Nixon at the rear, the Tigris Corps was compelled to a frontal attack on the Turk trenches, on both river banks. As the force approached on 6 January 1916, they were cut down by small arms fire. By nightfall, when it became obvious that no breakthrough could happen, the assaulting units were ordered to dig in.

Next day, the weather was awful: humid, with thick mist following heavy rain. Without heavy artillery, the British were ordered again to attack entrenched positions. The attacking infantry - notably the 1st Seaforth Highlanders, the 2nd Black Watch and Jats - were hit by concentrated crossfire. As the British moved forward into murderous fire, the Turks counterattacked and attempted to encircle on the right. The small British field artillery, together with the 41st Dogras and 9th Bhopals, fought this danger off. By nightfall, the position remained stalemate.

Later that night it was discovered that the Turks had withdrawn upstream. No one knew why. The Turkish commander Nur-Ud-Din was sacked as a result of this strange decision and he was replaced by Khalil Pasha.

British casualties at Sheikh Sa'ad were over 4000. The provision of adequate medical capacity and supplies had not been high on the list of priorities for the limited transport from Basra, and the underequipped Field Ambulances struggled to cope. The Meerut Division had capacity to cope with 250 casualties, but were faced with thousands. More than 1000 wounded men were still lying out in the open, with barely first-aid administered to them, 11 days after the fighting. Of these, 100 were suffering too from dysentery.

Some of the attacking units suffered proportionally very high losses: the 1st Seaforth Highlanders lost 20 officers and 380 men; the Jats lost 335 of 485. The 2nd Leicesters lost 16 officers and 298 men.

The Wadi was a steep valley of a stream that ran from the north into the River Tigris some 6 miles upstream towards Kut-al-Amara from Sheikh Sa'ad.

In January 1916, days were hot, foggy and humid and night was below freezing. It was a season of heavy rain: the ground was a quagmire, and the rivers swollen. At dawn on 13th January 1916 there was a thick mist.

Nixon maintained pressure on Aylmer to continue the forward march of the Tigris Corps to relieve Townshend's troops besieged in Kut-al-Amara. Despite the setback at Sheikh Sa'ad he remained optimistic. Aylmer was beginning to take a more realistic view. He was now facing Turkish troops that had seen action on Gallipoli. In total his column was now 10000 strong which with a similar number in Kut which when added together roughly equalled the Turkish forces in the area. However there were known to be another 30000 Turks at Baghdad with a similar number on the way from Turkey. Furthermore, the heavy rains normal for February and March would flood the Tigris and make further progress impossible. Time was of the essence. However, his supplies were disorganised and he still had too little transport.

Khalil Pasha had ordered the Turkish force withdrawing from Sheikh Sa'ad to halt and dig in on the banks of the Wadi, about 6 miles upstream towards Kut. It was a good position to defend and lay in front of a narrow strip of land called the Hanna Defile that lay between the River and the great Suwaikiya Marshes - through which the British would have to pass to reach Kut.

Aylmer planned to outflank the Wadi position, capture the Hanna Defile and surround the Turkish force. The 28th Brigade under Brig-Gen. Kemball would attack the Wadi trenches frontally, while the rest of the Tigris Corps moved around the flank. The British troops were hampered by having no accurate maps of the area, so much of the planning was left to chance.

The advance on 13 January 1916 was delayed to allow the morning mist to clear. It took much longer than anticipated for the artillery accompanying the flanking force to cross the steep-sided Wadi and it was not until 1pm until it was all in position. (In retrospect, there was no real need for the artillery to have moved this far; they could have shelled the Turk positions quite adequately from where they started the day). There was little Turk opposition in this area but the advancing infantry was so few in number for the distance to be covered that in many places they advanced beyond the Turkish posts, to be shot down from the rear. The delay had seriously affected the chances of success, as small-arms and artillery fire from the alerted Turks began to halt the British infantry moves. The Turkish units also began to wheel around from a north-south position to an east-west one, to keep facing the flanking manoeouvre of the British. The frontal attack by the 28th Brigade was completely repulsed, with heavy casualties. As dusk began to fall, it became clear that the attempt had failed. No British troops had got as far round the Turkish flank as to reach the river, and the mouth of the Hanna Defile was still held - indeed strongly entrenched - by the enemy.

The Wadi itself was now in British hands but the relieving force was really no nearer to Kut and the strengthening Turkish forces were holding on to their forward positions in what was to prove to be a most difficult obstacle at the Hanna.

British casualties at the Wadi were over 1600. The provision of adequate medical capacity and supplies had not improved significantly since the appalling debacle at Sheikh Sa'ad so again many casualties suffered without treatment or evacuation for several days.

The Hanna Defile is a narrow strip of dry land between the River Tigris and the great Suwaikiya Marshes - through which the British would have to pass to reach the besieged Kut. The mouth of the Hanna lies upstream of the Wadi, some 8 miles towards Kut-al-Amara from Sheikh Sa'ad.

In January 1916, days were hot, foggy and humid and night was below freezing. It was a season of heavy rain: the ground was a quagmire, and the rivers swollen. The weather was so bad just before this battle that it severely delayed the upriver movement of reinforcements and supply. It cleared up just as battle opened, but on the morning of the 21st January there was a thick mist and from mid-morning it poured with rain.

This battle took place only 8 days after the repulse of the Tigris Force at the Wadi.

The 3rd (Lahore) Division had recently arrived in Mesopotamia from France.

Lieut-General Sir Fenton Aylmer, OC Tigris Corps, was perplexed by the strong resistance of the Turks since the advance began. He signalled to both Sir John Nixon and Sir Charles Townshend:

The position of affairs must be frankly faced. The enemy is blocking the entrance of the Wadi-Nukhailet Defile (the Hanna) with very strong works ... it is impossible in my opinion to take the first position without losing half of my force. It is my intention to cross the 3rd (Lahore) Division and Cavalry Brigade to the right bank and thus enfilade the enemy's position. Even by this means I do not think that progress can be anything but slow

He also requested that fit men of Townshend's force in Kut leave the town by boat and cross to meet his proposed assembly. The sick and wounded would have to remain.

Nixon, ever optimistic, agreed with his tactics of crossing the river but forbade the action Aylmer had suggested for the besieged force.

On 16 January 1916, Townshend signalled that the garrison now had 21 days rations left for the British troops, 17 for the Indian, and 5 days fodder - so Aylmer had more time that previously thought (expectations set, of course, by earlier panic-stricken signals from Townshend).

At noon on 20 January 1916, the Turkish defences at the Hanna were bombarded for 20 minutes and were again the next morning. The bombardment was from both banks, and from gunboats. 12000 rounds in all were fired. Such paltry preparation would at this time have been laughable on the Western Front.

There was no attempt to deceive the Turks or any attempt at surprise. Not that there were many options, as the main assault would be on a very narrow front less than a mile across. No man's land was 600 yards deep.

The attacking units were very under-strength as a result of the earlier fighting and from sickness. The Meerut Division went into action with fewer than 4000 effective men. The 21st Brigade had to be broken up and its battalions attached to the other Brigades, the 19th and 35th.

The infantry attack went in half an hour after the last shell had fallen, in misty daylight, at 7.45am. The Turkish troops - virtually undamaged by the shelling - rose to man their trenches and cut down the infantry in swathes. Very few men reached their trenches. Owing to wet soil, shelling and losses among the operators, the field telephone system broke down almost immediately, leaving Brigade, Division and Corps completely in the dark as to what was happening. While various commands were given to reorganise and renew the attack, in the appalling weather and with such chaos in the front lines, no further effort was made.

Next morning, Aylmer asked the Turks for a six-hour truce to collect the wounded and bury the dead. As soon as he raised a white flag, Arabs swarmed out of the Turkish lines and began to rob the dead and wounded, collecting especially rifles. Many wounded were killed by them. Eventually Turkish officers stopped this sorry episode.

Everyone knew that the failure at the Hanna spelled disaster for the garrison in Kut.

British losses in this action amounted to 2700 killed and wounded. According to one commentator: 'In any history of sufferings endured by the British Army, the collective misery of the night of 21st January 1916 is probably without parallel since the Crimea'. There was complete breakdown of medical arrangements, due to the overwhelming number of casualties, the weather and ground conditions.

The Turkish Army had by March 1916 entrenched a position running perpendicular to the Tigris, some 10 miles east of Kut-al-Amara. The land in this area was completely flat, covered with thorny acacia bushes. At key points, they had fortified the line into redoubts and taken advantage of impassible swampy areas.

In March 1916, the weather was fine and clear.

After the defeat at the Hanna, Sir Percy Lake - newly appointed to command of the Mesopotamia theatre in place of the hapless Nixon - took an appraisal of the situation. The 6th (Poona) Division was still besieged in Kut, and Townshend's latest report was that supplies would last 84 more days (not the 22 days he had initially indicated, which forced the urgent early attempts at relief that had cost many men their lives). Lake had a little more time to plan; he told Townshend to hold on and wait to be relieved, even though Sir Fenton Aylmer (OC Tigris Corps) advised him against this. Reinforcements were now pouring into Basra; in fact there were more troops there than at the front, due to the lack of boats and ships to take them up river. In the whole theatre there were 63000 troops, although 1 in 8 was hospitalised and a further 15000 unavailable for fighting. Of the rest, only some 14000 were actually on the Tigris front, facing 35000 enemy.

Agents in Constantinople had supplied information that another 36000 Turks were on their way to the area from Gallipoli. Lake ordered a build up of three months reserves - which promptly created chaos at the few wharves and at the stores and depots of the base. It was not unknown for a laden ship to wait a month in the Shatt-al-Arab before it could be unloaded.

In February 1916, Chief of the Imperial General Staff Sir William Robertson recommended to the War Committee that the War Office should take control of operations in Mesopotamia. This was accepted by London and India, and marked a new beginning to this so-far disastrous campaign.

Lake left the detailed planning for the relief of Kut to Aylmer. He decided on a formidable frontal attack using the whole of his Corps up the right bank of the Tigris, across flat, arid desert, to take the Es Sinn position, from where Kut was visible. By capturing this, Aylmer hoped to cut Turk communicatios on the right bank and even force the enemy to evacuate the siege positions around Kut.

The Es Sinn trenches were strongly fortified where the 150-yard wide 6-foot deep gully known as the Dujaila Depression cut through them. This fort, or redoubt, was the key to the whole position. It was 10 miles from the advanced posts of the Tigris Corps.

Despite there now being a little less urgency to relieve Kut and knowing that the first units of the 13th (Western) Division were only just arriving from Gallipoli, Aylmer was for waiting until his force had been reinforced. Lake pushed him into an early attack. 15 March was the latest date at which they could reasonably expect the ground to be free of spring flooding. Meanwhile, a bombardment was kept up on the Hanna defile.

Two brigades (19th and 21st of 7th (Meerut) Division) and 24 field guns under Major-General Sir George Younghusband would make a diversionary attack on the enemy garrison in the Hanna positions, while three columns - designated A, B and C, together with a Cavalry Brigade, making over 37000 men in all, with 66 field guns - advanced towards the Es Sinn line. The advance began at 9.30pm on 7 March 1916.

Just before dawn the advance reached the place where Column C under Major-General D'Urban Keary (OC 3rd (Lahore) Division) split off towards the Sinn Abtar Redoubt. Columns A (under Brig.-General G. Christian) and B (under Major-General Kemball) moved directly for the Dujaila Redoubt while the Cavalry Brigade - which was to prove particulary ineffective in this action - moved to the southern flank. Patrols advancing cautiously at dawn found the enemy positions unoccupied: the British troops could have occupied them easily. But initiative was not a strong feature of this army at this time; they had to ask for orders, to be able to move beyond where they had already been ordered to go. Corps replied loftily that the artillery timetable was fixed and that the infantry should stick to the programme. In the three hours it took to bring the artillery up, and the leisurely period in which they registered onto target, all surprise was lost. 6000 Turkish troops were waiting for the attack when it finally came in.

The British advance was cut down by machine-gun and rifle fire from the Redoubt trenches at a distance of some 700 yards. By noon, they had gained only 200 yards. At 2.30pm, it was clear that the attack could not continue.

Keary's Column C - consisting of 7th and 8th Indian Brigades of the Lahore Division - facing the Sinn Abtar Redoubt also waited, in accordance with orders, for the attack to the south to begin before they did anything. This position had also been lightly held. Aylmer ordered them to attack at 4.30pm, by which time all activity at the Dujaila redoubt had ceased and the Turks could pay this area complete attention. Despite heavy fire and casualties, the leading battalions - the 1st Manchesters and 59th Royal Scinde Rifles - got into the Redoubt trenches. An immediate counter-attack using grenades forced them out again, but they were able to withdraw.

And what of 6th Indian Cavalry Brigade, out somewhere on the left? They had no effect on the battle whatever, spending much of their time behind the infantry. Townshend's garrison in Kut-al-Amara formed up a weak brigade ready to assist, but he ordered them to hold fast as it became clear to him that Kemball's attack had failed.

Once again, during the night the Budhoo gangs appeared, robbing the dead and killing the wounded who remained. The Turkish Army made no attempt to follow up.

British losses in this action were 4,000 killed and wounded. They had lost half their force without ever seeing the enemy. There was once again a complete breakdown of medical arrangements due to the overwhelming number of casualties, the weather and ground conditions. Some units were so reduced by casualties that they had to temporarily merge with others.

Aylmer was broken by this latest failure and was replaced as OC Tigris Corps by George Gorringe (left), newly promoted to Lieutenant-General. The Tigris Corps spent the rest of March consolidating and tidying up. Governor of Baghdad Khalil Pasha wrote to Townshend inviting him to surrender. But by now the men in Kut could hear the guns of the Tigris Force approaching and although conditions were critical, there was still room for hope.

For some miles along the left bank of the Tigris, there was a strip of dry ground between the river bank and the great impenetrable Suwaikiyeh Marshes. The Turkish Army held all of this ground and had cut at least three trench systems across it, at the Hanna, Fallahiyeh and Sannaiyat. Any British attack towards Kut on this side of the river would be frontal and on a very narrow front at that.

There were no roads in this area, and all movement and supply had to go along flooded tracks.

The Tigris Corps spent the rest of March consolidating and tidying up. Sir Percy Lake wrote to Townshend, assuring him that next time he would use "Maximum Force". In practice, this meant another battering-ram assault to break through the three Turkish lines, using the newly-arrived 13th (Western) Division and for the umpteenth time the 3rd (Lahore) Division and 7th (Meerut) Division. The latter two formations had already lost some 14000 casualties since their arrival on the Tigris front and their morale was very low. In the weeks of quiet between the Dujaila attack and the renewal, both sides entrenched.

The fine weather broke on 30th March.

Gorringe returned to the left bank of the river for his attack; the same defences at the Hanna that had proven impossible to break would have to be tried again.

The first effort was made on 5 April 1916, when after many days of bombardment and preparations the 13th Division made an attack on the Hanna positions, only to find that they were expected and the Turks had silently withdrawn to the newly-strengthened line at Fallahiyeh. The lead 40th Brigade pressed on the mile and a half to the new positions, where they came under heavy fire and had to fight off a counter-attack. After dark, the British artillery opened up on the Turk lines. At 7.30pm the 38th and 39th Brigades advanced, but they were cut down by machine-gun fire and in hand-to-hand fighting, lost some 2000 men in the process.

Next day, 6 April, the 7th (Meerut) Division relieved the survivors of the 13th. They had been led to believe that capturing the Fallahiyeh line would be easy, because the Turks were preparing a stronger defence six miles on, at the Es Sinn position. But nothing could be further from the truth. Without maps and without prior knowledge of the ground, the Meerut groped their way foward before dawn, into a hornets nest. 1200 men fell in 20 minutes. An order to renew the same attack 24 hours later came to nothing, as a strong wind made the waters of the Suwaikiyeh Marshes rise, flooding trenches and drowning wounded men.

At 9pm on 7 April, an artillery bombardment was fired just to raise some activity in the Turkish trenches so they could at least be spotted. The enemy obliged, firing Verey lights and sending up rockets. At least in the renewed attack, this time by the 13th Division having relieved the shattered Meerut, would know what they were aiming for. The attack went in at dawn on the 8 April. Some men penetrated the first Turk lines but were bombed out in intensive close fighting. Many men did not get that far: the Division lost another large part of its fighting strength - another 1600 men.

British losses in this action were thus some 4800 killed and wounded. They had achieved nothing in terms of ground gained and Kut was still besieged. The weather suddenly turned to violent storms. The misery of the men of the British Army on the Tigris could not have been more complete.

During the night of 8 - 9 April 1916, the 13th Division relieved the 7th (Meerut) in the trenches and at 4.20am advanced to the assault of the Sannaiyat position. When within 300 yards of the enemy fire trench they were discovered, and a shower of Turk Verey lights and flares exposed them to heavy small arms fire. Nonetheless, detachments of the 6th King's Own, 8th Royal Welsh Fusiliers, 6th Loyal North Lancashire and 5th Wiltshire managed to penetrate into the enemy lines. Unfortunately, the supporting second wave of infantry lost direction in the glare of the flares, leaving those initially successful parties alone. A Turk counter attack drove all British troops out of their trenches, and back some 500 yards. It was clear once again that the enemy positions here were immensely strong and could not be taken by frontal assault.

Despite the disappointment and heavy losses in the attack on Fallahiyeh, General Gorringe had little option but to continue the effort to relieve the desperate garrison in Kut.

Lake and Gorringe conferred. They agreed it would take too long to drive saps up to the enemy lines from the existing British positions, which would be the best systematic way to attempt an attack. The only option would appear to be to try to outflank the enemy line by attacking at the Sinn Aftar Redoubt on the Turkish right near the river, on the right (south) bank.

On 12 April, 3rd (Lahore) Division, advancing across belts of inundated ground intersected by deep cuts, drove in the enemy's advanced posts east of Bait Aisa and occupied their outpost line. Further small advances were made on the next two nights.

The main Bait Aisa position was attacked at 6.45am on 17 April by the same Division, attacking with 7th (Ferozepore) and 9th (Sirhind) Brigades. So swiftly did the infantry attack that the British artillery fire was still falling in the main Turk trenches when they reached them. As soon as the shellfire lifted onto more distant targets, the soldiers of the Punjabi, Mahratta and Burmese battalions moved in with the bayonet. More than 200 Turkish soldiers were killed in this ferocious attack, and 180 were taken prisoner. The 13th Division was ordered to relieve the Lahore that night, preparatory to continuing the attack next day.

But the Turks were in no mood to allow this success to be held. At 5pm, they began to bomard the lines of communication behind the advanced units of the Lahore Division, effectively cutting them off from reinforcement. British artillery replied to the SOS, but this did not stop the enemy from launching a counter attack which pushed the British back. The troops of 13th Division, moving up to relieve the Lahore, were delayed due to the state of the flooded ground and it was many hours later that they arrived to help stem the counter attack. Turkish attacks - at least six - continued through the night, despite heavy losses estimated at 4000 men.

Meanwhile on the left (north) bank, 7th (Meerut) Division had been cautiously sapping forward ready to assault the Sannaiyat line. British artillery opened a bombardment of the Turk trenches that lasted throughout the 20 and 21 April. The infantry of 19th (Dehra Dun) Brigade led the attack on 22 April, the front being confined to only 300 yards of passable ground with swamp on either side. The leading troops crossed the first and second Turkish trenches, but suffered losses to machine gun fire which meant that few got as far as the third line. A large enemy counter attack was initially held off, but a second attempt proved too strong for the weak parties holding the captured trenches, and they were forced to withdraw to the start point, reaching the British lines by 8.40am.

By mutual consent, parties of both Red Cross and Red Crescent went out to collect their wounded.

British losses in this action were estimated at 1,300 killed and wounded. Persistent and repeated attempts to break through to the relief of Kut had failed. It was known that there were by now no more than six days food left in the town (and this consisted of very meagre rations of mule, grass and other unpalatable fare). General Gorringe's Tigris Force was itself all but spent, exhausted after its efforts.

One last effort to resupply Kut was made, most gallantly, on 24 April 1916 when the fast steamer Julnar set sail from Fallahiyeh carrying 270 tons of goods under command of Lieutenant H.O.B. Firman, RN. Despite being covered by artillery and machine gun fire, aimed to distract and keep under cover the enemy, Julnar was seen, shelled and captured some 8.5 miles from Kut. It was all over. To the shame of the British, the Kut garrison was surrendered.