'Abbess' was a British contingency plan for the defence of Turkish naval bases in the event that Turkey entered the war on the side of the Allies (?).

Alone of the major powers which had been involved in World War I, Turkey managed to avoid military commitment in World War II, a fact reflecting the experience of all Turkey’s senior leaders, who had seen combat in that war and and the subsequent end of the Ottoman empire. On the outbreak of World War II in 1939, the Turkish civil and military leadership was all too aware of the fact of the total obsolescence of their armed forces, which would almost certainly have led to Turkish defeat in combat with either Allied or Axis forces. Mustafa İsmet İnönü, who had become Turkey’s second president in 1938 on the death of Mustafa Kemal Ataturk, and all his advisers therefore favoured neutrality. In historical terms, Turkey’s primary enemy had been Russia, but in 1925 Turkey and the USSR agreed a treaty of friendship, renewed in 1935, which seemed to have removed any threat from the north-east. During the 1930s, moreover, Turkey came to see its greatest threat as Balkan insecurity as a result of Italy’s territorial ambitions. By 1939 this threat had also become widely perceived in France and the UK, which had major interests in the eastern Mediterranean, and these two countries therefore began to consider alliances with Turkey. While Turkey was content to reach arrangements which would provide aid should the country be attacked by Italy or Germany, it did not wish to be drawn into war for the sake of the Allies.

During May 1939 Turkey and the UK issued a joint declaration that they would aid each other in the event of an act of aggression leading to war in the Mediterranean. Following an agreement with France which resulted in the transfer of the disputed province of Alexandretta from the French mandate of Syria to Turkey, the Turkish and French governments issued a similar declaration in June 1939. It was only a short time after this, though, that Turkey’s sense of improved security was shaken by the signature of the Nazi-Soviet Pact of August 1939, which created the spectre of German and Soviet collaboration against Turkey. Sukrti Saracoglu, the Turkish foreign minister, therefore travelled to Moscow in September 1939 in an unsuccessful attempt to arrange a mutual security arrangement. In light of this failure, Turkey once again attempted negotiations with France and the UK, and in October 1939 the three countries reached agreement on a tri-partite treaty providing that the two countries would aid Turkey if this latter were attacked by another European power. If there were an act of aggression leading to war in the Mediterranean area involving France and the UK, then Turkey would assist them, but would be exempted from any action in the case of a war between its two allies and the USSR.

The outbreak of war in Europe delivered Turkey into a time of considerable danger up to June 1941. Italy’s entry into the war in June 1940 began the battle for the Mediterranean, and the defeat of France in the same month meant that the UK would be unable to aid Turkey. Conversely, it meant that the UK appreciated the futility of seeking to oblige Turkey to fulfil its commitments under the tri-partite treaty. Subsequently, the German 'Unternehmen 25' and 'Marita' operations against Yugoslavia and Greece brought the war closer to Turkey, and in the case of the latter right to Turkey’s western frontier. Faced with the possibility of a German offensive toward Istanbul and both the Bosphorus and Dardanelles, Turkey signed a Treaty of Territorial Integrity and Friendship with Germany on 18 June 1941. This was a move with which the British approved as it lessened the chance of a German eastward advance into Asia Minor. Only four days later, Adolf Hitler launched the 'Barbarossa' invasion of the USSR, and this opened a second phase in the relationship of Turkey and World War II as it essentially removed, for the immediately foreseeable future, the threat of a German or Soviet invasion. İnönü strongly resisted the efforts of Franz von Papen, the German ambassador in Ankara, to enter Turkey into the war on the German side.

This second phase ended in the autumn of 1942, as the 2^nd Battle of El Alamein and Soviet resistance at Stalingrad indicated that the Allies were now likely to win the war. Until 1943 the UK, the USSR and later the USA were prepared to accept Turkey’s neutrality as the USSR was preoccupied by the war on the Eastern Front and the two Western Allies could not, as yet, undertake their grand strategic counter-offensive in Europe. Once this turning point had been passed, these concerns ceased to apply. Prime Minister Winston Churchill of the UK was especially concerned to bring Turkey into the war to open the war for a campaign against Germany from the Balkans. However, Churchill’s 'soft underbelly' strategy did not gain anything like full support from the USA, which was concerned that this would merely dilute the resources available for the primary effort, into France and then straight to the east into Germany, that lay at the heart of US strategic thinking. Turkey came under very strong pressure to join the Allies in the war in February 1943, when Churchill visited İnönü at Adana, and again at the 'Sextant' conference in Cairo in the following December.

The Turks demanded and received increased quantities of Allied war matériel, but still delayed an implementation of their undertakings of 1939. By 1944, relations between Turkey and the Allies (the UK and the USSR in particular) were therefore at a very low ebb. Turkey officially declared war on Germany only on 23 February 1945, but then only to establish its status as a founder member of the United Nations. In the meantime, Iosef Stalin reacted to Turkey’s non-belligerence by demanding political and territorial concessions. In June 1945, Moscow insisted that the Turkish-Soviet Friendship Treaty could not be renewed unless Soviet bases were established in the straits, and the provinces of Kars and Ardahan, on Turkey’s north-eastern frontier, were ceded to the USSR. Turkey refused these demands.