The surge in support for left winger Jeremy Corbyn had triggered a 'horrific week' for the Labour Party, senior figures warned today.

There is growing dismay among self-styled 'sensible people' in the party who fear Mr Corbyn's popularity is making them a laughing stock.

It comes after leaked polling suggested Mr Corbyn was ahead in the race to be the new Labour leader, despite being made the 100/1 rank outsider after entering the race at the last minute.

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Jeremy Corbyn is on track to top the first round of voting in the Labour leadership contest, leaked polling has claimed

Mr Corbyn's shock surge in support has triggered a war of words among rival camps, as it threatens to overshadow attempts to put the Labour Party back on the path to power after May's crushing electoral defeat.

Internal Labour polling was leaked yesterday putting Mr Corbyn up to 15 per cent ahead in the race to succeed Ed Miliband.

Rival camps have accused each other of leaking the results, with allies of favourites Andy Burnham and Yvette Cooper pointing the figure of blame at the Blairite candidate Liz Kendall.

One Labour MP said: 'It's a load of b******* put about by Liz's supporters because they're sore they are going to come last.'

The infighting exposes growing concern among senior members of the party over Mr Corbyn's popularity.

On shadow cabinet minister told MailOnline: 'What a horrific week for the sensible people in the Labour Party.'

Senior Labour MPs have publicly warned that a victory for Mr Corbyn would spell disaster for the party.

Shadow education secretary Tristram Hunt said the party needed 'shock treatment' to regain its senses or it could 'disappear and die' like Woolworths.

Chuka Umunna, the shadow business secretary who pulled out of the leadership race, today slammed Mr Corbyn's bid to drag the party further to the left.

He said: 'I don’t buy the argument that somehow a more full-throated left advocation of Labour values is somehow more true to our values - I don’t believe it is.”

Mr Umunna said the left winger gave the impression that Labour is 'more concerned with those who won’t work, [than those] who can work', adding: 'I don’t think is a way that we’re going to be able to win over people.'

He said: 'If we want to be an alternative and put ourselves forward as a serious, credible alternative party of government than we’ve gotta wake up and deal with the world as it is ... I’m sorry, the left of our party have no monopoly on the desire to build a fairer and more equal society.”

Jeremy Corbyn (second left) has collected more than 40 nominations from local parties - second only to the bookies' favourite Andy Burnham (right) and ahead of shadow home secretary Yvette Cooper (left) and shadow care minister (second right)

While Mr Corbyn's surge has sparked panic among Labour MPs, it has been actively encouraged by the Conservative Party.

It emerged today the Mr Corbyn has even received face-to-face advice on how to win the Labour leadership - by David Cameron.

The Prime Minister bumped into the hard Left MP in the House of Commons ahead of a meeting with Conservative MPs late on Wednesday afternoon.

Mr Cameron said Mr Corbyn should model his campaign on his own successful bid to overhaul David Davis in 2005's Conservative leadership battle.

Speaking to a private meeting of the Conservative 1922 committee, Mr Cameron said he told the Labour MP: 'You have got to be the change candidate – I was the outsider.'

Mr Corbyn, a veteran socialist who believes Ed Miliband was not left wing enough to win the election, is understood to be leading rival candidates by up to 15 per cent in the first round of votes.

The 66-year-old backbencher has already shocked Labour MPs with the surge in support he has enjoyed among ordinary party members since joining the contest at the last minute.

He has collected more than 40 nominations from local parties - second only to the bookies' favourite Andy Burnham and ahead of shadow home secretary Yvette Cooper.

David Cameron gave advice to Mr Corbyn on how to win the Labour leadership

The Blairite candidate Liz Kendall, in contrast, has won the support of just five local parties.

But, according to internal polling seen by the Labour-supporting political magazine The New Statesman , Mr Corbyn is even further ahead among individual members.

One survey puts Mr Corbyn in what one member of a rival campaign called 'a commanding position', adding: 'He is on course to win.'

Mr Corbyn's campaign was given a further boost yesterday after Britain's biggest trade union boasted it was on course to flood Labour's leadership contest with up to 70,000 new voters.

Mr Corbyn, 66, was endorsed by Unite to succeed Ed Miliband earlier this month.

The veteran backbencher today moved to cement his support among grassroots supporters by promising to scrap student fees.

He said he would pay for the £10 billion reform by raising tax on company profits and higher National Insurance payments for higher earners.

Mr Corbyn issued an apology 'on behalf of the party' to the generation of students hit by Labour-imposed tuition fees and said he relished the 'opportunity to change course' and match the no-charge policy of Scotland and many European countries.

Under one of two options to pay for the student finance shake-up corporation tax - which Chancellor George Osborne announced in the Budget would be cut to 18% by 2020 - would be put back up to 20.5% to fund the £3 billion cost of maintenance grants.

And the £7 billion in lost fee revenue would be replaced through a 7% rise in National Insurance contributions on anyone earning £50,000 or more a year.

The alternative would be to slow the rate of deficit reduction by devoting two-thirds of an anticipated £15 billion increase in income tax receipts between 2019/20 and 2020/21.

Mr Corbyn, who unveiled recently-elected National Union of Students welfare vice president Shelly Asquith as head of his student campaigning, said he would consult members and supporters on the details.

'Education is not about personal advancement but is a collective good that benefits our society and our economy,' he said.

'I want to apologise on behalf of the Labour Party to the last generation of students for the imposition of fees, top-up fees and the replacement of grants with loans by previous Labour governments.

'I opposed those changes at the time - as did many others - and now we have an opportunity to change course.