Brown resists calls to sack 'troublemaker' Miliband as his popularity hits historic low

Labour MPs told the holidaying Prime Minister he would look weak if he failed to fire Mr Miliband for his 'duplicitous' behaviour.

But there was grim news for both men last night as an opinion poll suggested that whoever leads the party at the next election will not be able to save it from a major defeat.

Labour MPs are calling for Gordon Brown to sack David Milliband after he failed to defend the Prime Minister's leadership

It came on a day in which Mr Brown's allies retreated from their attacks on the Foreign Secretary but Mr Miliband showed no sign of wanting to dampen speculation about his intentions.

Downing Street had been taken aback at his decision earlier this week to set out a personal manifesto for beating the Tories at the next election  -  with no mention of Mr Brown.

Yesterday the Foreign Secretary conducted an extraordinary Radio 2 phone-in in which a series of callers demanded that he get rid of the 'God awful' Prime Minister  -  and then he signed autographs for admirers outside the BBC studio.

Mr Miliband repeatedly refused to say he did not have ambitions to get his hands on the keys to No 10. He simply said he was not worrying now about his 'next job'.

And he failed to give an unqualified endorsement of Mr Brown. Pressed about his attitude towards the Prime Minister, Mr Miliband said: 'I have always wanted to support Gordon's leadership.'

MPs loyal to Mr Brown noted that his words left the duration of his support unclear.

It also emerged last night that the Foreign Secretary has called off a trip to India at the start of September  -  the most likely moment for a party coup.

Geraldine Smith and Bob Marshall-Andrews have both called for Miliband to be sacked

Sources insisted the reason was because of Cabinet meetings planned for that week.

Mr Miliband, 43, also rejected suggestions from some of Mr Brown's allies that it was time for him to 'shut up'. 'I think the worst thing at the moment would be if we all went mute,' he said.

'It's right that we say that, sure we've taken some hits, but actually we've got ideas about the future of the country, we do want to engage with people.'

Two Labour backbenchers said Mr Brown should sack the Foreign Secretary.

Geraldine Smith said Mr Miliband was 'trying to stir up trouble' and said he should be fired by Mr Brown, returning him to being a 'nonentity' on the backbenches. She added: 'What has Mr Miliband ever achieved apart from furthering his own career?'

Another MP, Bob Marshall-Andrews, accused Mr Miliband of 'pretty contemptible politics' and said his behaviour had been 'duplicitous'.

Former Europe minister Denis MacShane warned the sniping against the Foreign Secretary risked undermining his authority on the world stage. He said: 'I think that the No10 briefers against Miliband, whoever they are  -  it's a bit like being ravaged by a dying rat  -  should go back into their holes.'

Some of the Prime Minister's allies privately accepted that the retaliation against Mr Miliband had gone too far.

A spokesman for Mr Brown said: 'We agree with David that the whole party should pull together, take the fight to the Tories and focus on dealing with the real issues affecting people's lives.'

But the YouGov poll for today's Daily Telegraph found Mr Brown's popularity at an all-time low. Barely one in seven voters believes he is fit for the job of Prime Minister.

It also found no Cabinet minister would be able to boost Labour's ratings significantly if they took over.

With Mr Brown as leader, only 25 per cent said they would vote Labour, against 47 per cent for the Tories.

However, with Mr Miliband in the top job, Labour support drops to 24 per cent, while under Justice Secretary Jack Straw the figures would also be 24 per cent to 45 per cent for the Tories.

...aren't you meant to be on holiday Dave?

Only last month, David Cameron suggested that Gordon Brown was not taking enough time off work.

Suspicion that his concern may have been tongue in cheek hardened this week with the Conservative leader's unwillingness to take his own advice.

Indeed, his family holiday in Cornwall seems to have been one long photo opportunity.

Pictured right is the Cameron holiday so far - a couple of days on the beach, a question and answer session with readers of the local paper and a visit to a farmers' market.