Harriet Harman has written to all Labour MPs asking them to check new members are not trying to skew the party's leadership contest.

Each MP has been sent a list of new members from their constituency so they can check for suspicious names.

It follows claims, denied by the party, of non Labour supporters signing up to back left-wing candidate Jeremy Corbyn.

Meanwhile, a review following the party's election defeat said an anti-austerity platform was "a vote loser".

The study, led by the party's former policy chief Jon Cruddas, found that "the Tories didn't win despite austerity, they won because of it".

In a poll of 3,000 people in England and Wales conducted for the party, 58% of voters agreed cutting the deficit was the "top priority", with 16% disagreeing.

But some 60% also agreed the economy unfairly favours powerful interests and 43% said they would vote for a party that would redistribute wealth from the rich to the poor.

'Integrity'

BBC political correspondent Alex Forsyth said Ms Harman's decision to write to MPs was part of ongoing efforts to ensure a robust contest rather than a result of particular concerns.

In the email, Ms Harman asks MPs to use their "local knowledge and information" to "uphold the integrity of the leadership election".

She tells them to raise any concerns about the names on the list with officials.

Last week Ms Harman told the Guardian a similar email had been sent to constituency Labour parties.

Labour leadership contest

Image copyright Getty Images Image caption Liz Kendall has been urged to back Andy Burnham or Yvette Cooper to defeat Jeremy Corbyn

Who are the candidates? Andy Burnham, Yvette Cooper, Jeremy Corbyn, Liz Kendall

Andy Burnham, Yvette Cooper, Jeremy Corbyn, Liz Kendall Dates: Ballot papers will be sent out on 14 August; voting can take place by post or online. They must be returned by 10 September. The result is on 12 September

Ballot papers will be sent out on 14 August; voting can take place by post or online. They must be returned by 10 September. The result is on 12 September Who can vote? All party members, registered supporters and affiliated supporters - including those joining via a union

All party members, registered supporters and affiliated supporters - including those joining via a union What is the voting system? The Alternative Vote system is being used so voters are asked to rank candidates in order of preference

The Alternative Vote system is being used so voters are asked to rank candidates in order of preference How does it work? If no candidate gets 50% of all votes cast, the candidate in fourth place is eliminated. Their second preference votes are then redistributed among the remaining three. If there is still no winner, the third place candidate is eliminated with their second preferences (or third in the case of votes transferred from the fourth place candidates) redistributed. It is then a head-to-head between the last two candidates

At-a-glance profiles of the four contenders

Labour is allowing people to sign up for £3 as a "registered supporter", which entitles them to vote in the leadership contest alongside regular party members.

Anyone signing up is asked to confirm: "I support the aims and values of the Labour Party."

But there have been warnings from some within the party of known "hard left" activists registering.

John Ferrett, leader of the Labour group on Portsmouth City Council, told BBC Radio 4's The World at One the names of a local Conservative activist and a member of the Trade Unionist and Socialist Coalition appeared on a list he had seen.

MP blocked

But Labour MP Fabian Hamilton said he had seen "no evidence" of other parties and groups trying to hijack the contest.

Labour says it has a "robust system to prevent fraudulent or malicious applications" with all applications checked against the Electoral Register.

Image caption Conservative MP Tim Loughton's attempts to sign up have been foiled

The party also said it had blocked an attempt by Conservative MP Tim Loughton to register to vote in the leadership election.

Mr Loughton said he was never going to actually vote in the election, but paid the £3 to register and was planning to expose Labour's slip-up if he had received voting papers.

Labour said: "While we are delighted to hear Tim shares Labour's aims and values, unfortunately he won't be able to vote in our leadership election.

"We would like to thank him for his generous donation to the Labour Party which we are keeping. If he wants to donate more money he is very welcome to do so via our website."

Ballot papers will be sent out on 14 August for the contest to replace Ed Miliband.

Mr Corbyn secured more nominations from constituency parties than any other candidate, although this has no direct bearing on the result.

The popularity of his campaign has sparked warnings from rivals Andy Burnham, Yvette Cooper and Liz Kendall - as well as other senior party figures - about a move to the left.

On Twitter, his campaign team announced it had raised £50,000 in 13 days, having aimed to hit the target in 50 days.