Amol Rajan: Exclusive! Cable buckling under "unbearable strain". (May, 2015)

The Lib Dem leader is in trouble after the leak of a memodetailing his hopes for a "progressive alliance".

A time capsule landed on my desk yesterday morning. From what I could make of the inscription - it was terribly faded - it held a news report from May 2015.

By Amol Rajan, Political Editor (Content)

Vince Cable was late last night said to be "buckling under the unbearable strain" after a week of intense negotiation with senior colleagues. The Liberal Democrat leader, who succeeded Nick Clegg after the party lost 17 seats in the election, has asked for "calm and composure" from members furious at a leaked memo to party President Tim Farron, in which he flirted with the idea of a "grand bargain" with Ed Miliband's rejuvenated Labour Party, resulting in the formation of a new party.

In the memo, revealed exclusively in i yesterday, Mr Cable wrote of his "date with destiny" in returning Britain's third party to its "historic home", a so-called progressive alliance. "As a former Labour Party member and indeed councillor", Mr Cable, 72, wrote, "I cannot ignore the ideological appeal of Ed Miliband's offer".

He went on: "All political parties are coalitions, but some more than others. I come from the Social Democrat wing; Nick [Clegg] and David [Laws] come from the Liberal wing. It would be remiss of me not to entertain the possibility of a social democratic alliance with the Labour Party that would deliver the 21st century to Britain's centre-left, and that is why I am writing to you in confidence."

Mr Cable, who has been accused of orchestrating the leak of the memo, has had tense relations with David Cameron and George Osborne since the new year, culminating in a heated exchange on the BBC's Andrew Neil Show in which the Chancellor accused him of being a "scrofulous socialist Scrooge". Last night the clip had 64 million YouTube views.

Because the Conservatives won 14 more seats than Labour in the hung parliament, another so-called Lib-Con coalition could be arithmetically more stable than a Lib-Lab alliance. Mr Miliband is understood to have offered Mr Cable the keys to No 11 if he goes into Coalition with Labour. On Monday, a senior ally of Mr Cable told i that he has rejected the idea of a Lib-Lab coalition, instead proposing a merger of the two parties under a new name, rumoured to be 'the New Social Democrats'. Mr Cable has until Friday to make a decision.

Mr Clegg was not available for comment yesterday, but a spokesman said the former Deputy PM was "unspeakably thrilled" by his new role as President of the European Commission and looking forward to spending more time with his three sons.

But what did Mr Cable do next?