ED MILIBAND could be ready to challenge Sir Keir Starmer for Labour’s leadership after the May elections in a further blow to the Prime Minister’s faltering position.

The Energy Secretary, widely regarded as one of the few Cabinet members to have made a fist of his job, has repeatedly denied any such intention, but the Star understands he is open to reconsideration.

He has become increasingly outspoken during the recent crisis over Peter Mandelson, and bluntly told the media this week that it had been wrong to name the now-disgraced New Labour grandee as ambassador to Washington.

His stock has risen across much of the left, although some sections would still regard him with scepticism.

But few would dispute that he could cope with the Prime Minister’s job from day one, whereas there are more doubts about former deputy premier Angela Rayner’s readiness.

Mr Miliband led Labour to defeat in the 2015 general election, which must count against him. He is now understood to have formed some sort of an alliance with Home Secretary Yvette Cooper, further to the right in the party, and one of the candidates defeated by Jeremy Corbyn in the 2015 leadership race.

Both are clearly dissatisfied with Sir Keir’s hapless leadership, and much of the Cabinet has expressed disapproval of his sacking of Foreign Office mandarin Olly Robbins, merely the latest official sacrificed to protect the Premier from the consequences of his own misjudgements.

Left MPs are also debating whether to run one of their own for Labour leader once the elections on May 7, widely anticipated to be disastrous for the party, are over.

The support of 81 Labour MPs is required to stand for Labour leader under undemocratic rules introduced by Sir Keir, which is more than twice the number of MPs affiliated with the Socialist Campaign Group.

However, putting a candidate forward would allow socialist MPs to advocate for the radical change in government policy needed, even if they are forced to eventually row behind a “soft left” alternative.

Names being floated include the group’s secretary, Leeds East MP Richard Burgon, Clapham and Brixton MP Bell Ribeiro-Addy, who ran a spirited campaign for party deputy leader last year.

To add to the Premier’s woes, Hull MP Karl Turner, recently deprived of the Labour whip, inadvertently revealed that he had written to the Commons Speaker Lindsay Hoyle asking for a probe into Sir Keir for misleading Parliament.

His letter, which Mr Turner breached protocol by briefly publishing before removing, charges the Prime Minister with misrepresenting to MPs evidence given by Sir Olly to a Commons committee this week.

Sir Keir himself claimed today it was business as usual and that the government was “working really hard on a huge amount of issues.” He claimed that the fuss over the Mandelson appointment was an attempt to deflect him from his agenda.

Cabinet Secretary Cat Little added to the obscurity of the episode, telling the foreign affairs committee today that Sir Olly had refused to give her the summary of the vetting report on Lord Mandelson.