The History of the Corps of the Royal Engineers
Volume VI    Gallipoli, Macedonia, Egypt and Palestine 1914-18
(by the Institution of the Royal Engineers 1952  - PRO Lib 358-20941)

Changed situation in December 1915.
It was obvious at the beginning of October that the imminent invasion of Serbia by the central Powers and Bulgaria would take place.  If it did succeed (as it did wihin a few weeks) it would give the enemy the use of the trunk railway from Vienna through Belgrade and Sofia to Constantinople.
The Sea transport was totally inadequate for keeping the engineers supplied with materials for the work demanded.
The weather opened its offensive with gales on the 8 September the 9th, 27th and 31st. They did considerable damage for the piers at Sulva, Anzac and Helles, seriously interrupted shipping services and wrecked many lighters and small crafts with the result there was a dramatic drop in the supplies of all war-like types of store.

7 December
Orders to evacuate Sulva and Anzac but to remain at Helles.
Anzac - reserves and supports withdrawn first and then the remaining troops in one, bound from the front line to the boats.
Sulva - final scheme similar to Anzac but modified because the defences were constructed to protect what were called Reserve Areas near the beaches.  The number of embarking points was to be increased by using trestle piers assembled beforehand and hidden until the last moment.
Various devices were prepared for the automatic firing of rifles and bombs after the troops had left.  A large mine was exploded on Russell’s Top to cover the final withdrawals.
All put into operation on the 8th Decemeber 1915.

By 18/19 December guns, animals, vehicles and stores were to be withdrawn (took 10 days to complete) leaving a garrison of 20,000 in each place.

Total withdrawn	83,048 officers and men
			186 guns
			2000 vehicles
			4,695 horses and mules
Not a single man, horse of gun was lost at Sulva and only 1 casualty at Anzac.