Although Britain sent a task force to the area during the crisis in 1974, the Americans vetoed military action to deter Turkey, he said.
In an interview published today in The Times Higher Education Supplement, Lord Callaghan implies this was because the US did not want to jeopardise its electronic spying bases in northern Cyprus. He admits the 1974 invasion, prompted by a Greek coup, left the US free to continue spying on Russia and the Middle East from the Turkish-occupied north - a statelet it does not recognise. "The Turks were willing to let the Americans carry on operating because their presence was a political safeguard against the Russians," he said.
While East Germans celebrated 10 years of freedom this week, Cyprus remains split by a Berlin-style wall.
America's use of spy bases in northern Cyprus has never been confirmed before. The revelation is to be raised in the Commons by the Labour MP Andrew Dismore, who said: "Even if there was no explicit official US support for the 1974 partition, there was clear benefit to Nato, in that military and intelligence bases were allowed to continue."
Brendan O'Malley is co-author with Ian Craig of "The Cyprus Conspiracy: America, Espionage and the Turkish Invasion"