Gordon Brown has backed Yvette Cooper for the UKLabour Party leadership.
The former prime minister’s office announced he had given the shadow home secretary his first preference vote.
In a recent speech, Mr Brown issued a thinly veiled warning to the party not to pick left-winger Jeremy Corbyn but gave no endorsement to any of his three rivals.
But his office confirmed that he believed Ms Cooper was the best of the quartet to succeed Ed Miliband at the head of the Opposition – and had already cast his vote.
His second preference was Andy Burnham and third Liz Kendall, it said ahead of a weekend appearance at the Edinburgh Book Festival where he will set out his choice.
In his only previous intervention, a high-profile 50-minute speech in London, he did not mention front runner Mr Corbyn by name – viewed as unelectable by many Labour MPs – but warned of the consequences of retreating to becoming a “party of protest”.
Burnham rally
Meanwhile, Mr Burnham called for unity and warned against infighting at a rally in London last night, saying the party should unite in opposing the government and fighting for power, rather than “turning inward and talking to ourselves”.
Speaking at a rally at St Pancras Parish Church in north London, Mr Burnham said: “The longer this contest goes on, the more Labour risks turning inward and talking to ourselves.
“I am very clear that under my leadership we will have the strongest opposition ever – taking on the Tories, getting after them day in day out, setting out a clear and radical alternative.”
The speech came as Mr Corbyn rejected claims the party would split if he were elected.
Senior party figures are expected to meet today amid concerns card-carrying Tories signed up as Labour supporters under new rules in order to vote for radical candidate Mr Corbyn, the one they believe will keep the Conservatives in government.
PA