Former British prime minister Gordon Brown's attempts to hold on to power were thwarted by Nick Clegg's demand that he step aside as part of any coalition between Labour and the Liberal Democrats, it was reported today.
The Lib Dem leader informed him to his face that a Lib-Lab alliance would only be possible if he bowed out.
According to Peter Mandelson's memoirs, former prime minister Tony Blair also told Mr Brown after May's inconclusive general election that the public would not accept him remaining in office.
After further calls for him to go from other senior Lib Dems, he announced he was resigning as Labour leader to allow coalition talks with the Lib Dems to continue. Ultimately the Lib Dems formed a coalition government with the Tories.
According to the account of Labour's coalition negotiations after the May 6 poll, Mr Brown went so far as drawing up a proposed Lib-Lab cabinet featuring Mr Clegg, Vince Cable and Paddy Ashdown as he plotted how to keep David Cameron out of Number 10.
But Mr Clegg, now the deputy prime minister, told Mr Brown he had to quit if there was to be a deal between their two parties.
Mr Mandelson records in his book, The Third Man, that at a meeting in the prime minister's Commons office on the Sunday after the election, Mr Clegg said: "Please understand I have no personal animosity whatsoever. But it is not possible to secure the legitimacy of a coalition and win a referendum unless you move on in a dignified way."
It was not until the following day, after conversations with other Lib Dems and his predecessor Mr Blair, that Mr Brown resolved to resign.