Dave Mann commented on an earlier post, “the times were a muddle of friends becoming foes and vice versa. Nobody could keep up with it.” True enough.
[A]another interesting fact about how Turkey entered the war [says Dave] is the Ottoman Empire was initially no great enemy of Britain and in fact they had contracted to buy two battleships from them before the war. When war broke out [Churchill unilaterally] reneged on the deal saying "sorry chaps but we need them more than you do now." Germany responded by sailing a battleship squadron up the Straits on a state visit and then proceeding into the Black Sea where they shelled some Russian naval installations while falsely flying an Ottoman flag. The flag story might be apocryphal, but the result was that Turkey was drawn into the war on the German side and when the squadron returned to Constantinople the Germans handed over their two battleships to the Sultan saying "Here ya go mate. This will compensate you for the two battleships that the Brits withheld from you!"
The story is not entirely apocryphal, only a little more complicated.
The Kaiser would have liked the gift to have been accepted that way, but for the Turks bore no ill will towards Churchill's seizing of the two battleships under construction; but (under German command) the Goeben and Breslau did bombard the Russian coast in an attempt to draw Turkey into the war, after which the Turkish Cabinet issued a note of apology to Russia.
The reforming Young Turks had replaced the Ottoman monarch and taken control of Turkey in the name of constitutional reform -- placing them closer to British constitutional arrangements than to Cazerist Russia's -- and were in no mind to join either Germany or any alliance that included a Russia with grand designs on Constantinople and former Ottoman territories in the Balkans and Persia. They wanted to stay out, so much so that at one stage the Goeben and Breslau (sent by the Kaiser as a bribe he hoped would get them on side) were stuck at the Dardanelles between British warships and Turkish forts, not knowing which direction (if any) might offer them safe harbour - and Liman Von Sanders, sent to Turkey as "military adviser" to marshal Turkish troops on Germany's behalf, was sending telegrams home that the anti-German atmosphere in Constantinople made it "almost unbearable for German officer to continue their service there."
The Turks only admitted the two German ships after extracting severe concessions from Germany, the transfer of the ships into Turkish ownership ), and no promise at all to join the war on their side or any other -- prompting Sanders to sling threats of going home, and of duelling with Young Turk leader Enver Pasha.
The Turks expected Goeben and Breslau to stay in port. The bombardment of the Russian coast Goeben and Breslau was ordered by their disgruntled German commander, forced to fly a Turkish flag after ownership was transferred, under which German sailors were now enlisted in the small Turkish navy under German naval officers wearing fezzes. It happened without casualty, without Russian retaliation, and without Turkish permission.
What swayed Turkey in the end towards Germany was not either battleships or bombardment but, first, the fear (justified in the end) that if the Allies won they would forcibly partition the Ottoman empire and deliver Constantinople to Russia, whereas German wouldn't; and, second, a man called Winston Churchill.
Without reference to his Cabinet, without any declaration of war, and in response to the bombardment which German sailors had carried out and for which the Young Turks had already apologised, Churchill ordered the Royal Navy on the afternoon of 31 October 1914 to "commence hostilities at once against Turkey".
It was by that action and no other that Turkey recognised that they had joined the war against the Allies -- not by any action of their own, but because one Allied politician had decided they should.
But it gets worse.
The place Churchill ordered the British squadron to attack was the Dardanelles -- which as far back as August 1914 Churchill had wanted to force on behalf of Russia.
The cost of the premature attack far outweighed whatever advantages Churchill hoped to gain by it -- , and as an indirect result Anzac forces were sent to die on Turkish beaches that had been signalled by Churchill as needing defence.
Because not only was Turkey now in the war against the British Empire when if had never desired any such thing, but "the Turks and their German military advisers [had now been put] on the alert. From that moment there was no possibility of surprise, and the Turks began to pay special attention to the defence of the Straits" that later on would cost so many lives to abortively try to force. 
It was an abortion wrapped in a clusterfuck rolled up in a complete bloody shambles.
This post is part of NOT PC’s #CountdownToAnzacDay. Other posts in the series:
- Countdown to Anzac Day
- Q: But what were the ANZACs fighting *for*?
- Q: So why were Britain and NZ at war with Turkey at all?
- Q: So why was WWI so calamitous?
- Q: Who started the whole bloody mess?
- The Horsemen of non-apocalypse
- War and Peace
 Trumpener, Ottoman Empire, p. 33
 Gilbert, Churchill: The Challenge of War, p. 216
 "Churchill was very keen on attacking the Dardanelles from a very early stage ... he was very keen to get to Constantinople somehow." Director of Military Operations Calwell, 'Dardanelles Commission: Evidence,' Q.3665.
 See Marder,’s From the Dreadnought to Scapa Flow, Vol II, pp. 83-5, and Robert Rhodes James’s, Churchill: A Study in Failure, 1900-1939, pp. 63-77