|Gen, Sir Ian Hamilton|
|Gen. Sir Charles Monro|
He would find support from another direction: the growing demands of the Balkan Front. As I noted in discussing the Mesopotamian Campaign, Bulgaria had finally entered the war on the Central powers side, and promptly attacked Serbia, which was already partly occupied by Austria-Hungary, thus giving the Ottomans the prospect of a direct rail link with Vienna and Germany. Though a bit peripheral to the Middle East proper, the British and French sought to shore up a collapsing Serbia by landing a military force at Salonika (Greek Thessaloniki) in Greece. They did this despite opposition from a divided Greek government. In the end it was too late to save Serbia, so the rationale became defending Greece (whether it liked it or not) against the Ottomans and Bulgarians.
The French would send mostly colonial troops and the Russians and other allies would send token forces, and remnants of the Serbian Army who escaped through Montenegro and were evacuated by Italy would join them, but the obvious source of British Empire troops were the ANZAC, British, and Irish troops stuck at Gallipoli. Already on September 30 the 10th (Irish) Division left Gallipoli, landing at Salonika October 5. The troops on Gallipoli were clearly not going to take Constantinople, so Salonika, despite the crushing of Serbia, and were thus a potential source of troops.