During a Downing Street party for journalists last summer, David Cameron's chief of staff entered and told him, "Netanyahu's on the phone". Exit Prime Minister.

"Ah, the old Israeli PM ruse," the BBC's Nick Robinson knowingly told his colleagues, as he recalled in his account of last year's general election, Election Notebook.

Apparently, when Gordon Brown was PM, if he wanted to leave a meeting, an official would come in and declare there was a call waiting from the Israeli premier.

But Robinson - now a presenter on Radio 4's Today - said that, after he'd left the party, he received an email about Cameron's call with Netanyahu. Either the exit code had changed, he reflected, or "the bluff has become even more elaborate".