The defence of Jerusalem, 26-30 December 1917, was the last significant action during the British invasion of Palestine in 1917. Jerusalem had fallen on 9 December, but the British line north of the city was rather ragged. General Allenby decided to mount one further offensive, with the aim of pushing the Turks back to a line ten miles north of the city, running from Beitin to Nalin. This would then join up with the right flank of XXI corps, on the coastal plains.
The Turks were also planning an offensive. Fresh troops had been found to make an attempt to recover Jerusalem (amongst them the Turkish 1st Division), and an attack was planned for the night of 26/27 December. The British offensive, planned for 24 December, had to be postponed due to poor weather. The British then intercepted a Turkish radio message and learnt of the planned Turkish counterattack.
The British plan was modified to take this into account. The two divisions on the British right were to stand on the defensive north of Jerusalem, while the two divisions on the left (74th and 10th Divisions) would launch their attacks as planned on the morning of 27 December.
The Turkish counterattack began on the night of 26/27 December. Its main focus was the hill of Tel el Ful, three miles to the north of Jerusalem, and just east of the road to Nablus. The fierce Turkish attack continued into the afternoon of 27 December but was unable to make any progress against the prepared British troops.
To the west the British attack made much better progress. During 27 December the two divisions on the left advanced 4,000 yards along a six mile front, threatening the right flank of the Turkish counterattack and forcing the Turks back onto the defensive.
On 28 December the entire XX corps joined in the offensive. The Turks were pushed back slowly on the first day of the general offensive, but their resistance soon began to fade, until on 30 December the British were able to advance to their original objective, the Beitin-Nalin line, against very little resistance.
This was the final significant fighting in Palestine until the spring of 1918. The British had outrun their supply lines on the advance from Gaza and needed time to prepare for any new advance, while the Turks had suffered very heavy casualties during the two months since the British attacked at Gaza. The weather also played a part. Heavy rains made any movement difficult, and washed out part of the existing railway.