By the end of August 1915, the last sputtering efforts of the British "August offensive" at Gallipoli had ended in a mix of British confusion and Turkish successes. Though two more units would be landed as reinforcements in September, Britain had shifted to the defensive. The Gallipoli campaign had failed By November it would be decided, after a visit by Lord Kitchener, to pull out, but fears of massive casualties made this a slow process, and the last British troops were not removed from Turkish soil until January 1916. Casualties were kept relatively low after the failure became apparent, except at the senior level: General Sir Ian Hamilton would be relieved in October, and his advocacy of Gallipoli would haunt Winston Churchill's career for decades.
But the increasingly obvious failure at Gallipoli would not be the only bad news for Britain in the Middle East. In Mesopotamia the British were overextending their Mesopotamian campaign, a mistake that by the next year would lead to their disastrous surrender at Kut.
Even more critically, in October 1915, Bulgari would enter the war on the side of the Central Powers opening up an overland line of communications between Germany and Austria-Hungary and the Ottoman Empire, and facilitating rearming the Turks. British fortunes in the Middle East were clearly on a downturn a century ago.