Image copyright Getty Images Image caption Labour's new leader will be elected in less than a week's time

Labour MPs must "work with" whoever is elected leader later this week, Harriet Harman has said.

The party's acting leader said Labour had to rebuild with an effective opposition leader and also someone who was "electable" as prime minister.

Leftwinger Jeremy Corbyn remains the frontrunner ahead of Saturday's poll.

Ms Harman said she was "absolutely confident" the result would be legally sound, with Labour having weeded out 4,000 people not entitled to vote.

'Valid' process

Ms Harman told the BBC's Andrew Marr show Labour had conducted "due diligence" on the thousands of non-party members who have paid £3 to register to vote and blocked people deemed to be infiltrators from rival parties or organisations from taking part.

Whoever is elected on Saturday would be a "valid" winner, she said, with more than 500,000 people having taken part in the contest.

Image caption Ms Harman said she remained "scrupulously neutral" in the leadership contest

Several leading frontbenchers have said they will not serve under Mr Corbyn's leadership while others have said the veteran MP will take Labour in the wrong direction on the economy, Europe and in foreign affairs.

Ms Harman, who will step down from frontline politics on Saturday, said she remained "scrupulously neutral" in the contest, in which Andy Burnham, Yvette Cooper and Liz Kendall are also standing.

And she suggested that the party would have to rally round Mr Corbyn if he won.

"Obviously we want a Labour leader who is going to be an effective leader of the opposition and a prime minister," she said.

"Whoever is chosen, we will all need to be working with to get ourselves electable."

Labour leadership contest

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

Dates: Ballot papers were sent out on 14 August; voting can take place by post or online. They must be returned by 10 September. The result is announced on 12 September

Who can vote? All party members, registered supporters and affiliated supporters - including those joining via a union. More than 160,000 people signed up to vote as supporters, full members or union affiliates in the final days before the registration deadline, bringing the total size of the electorate to 610,000

What is the voting system? The Alternative Vote system is being used, with voters asked to rank candidates in order of preference

How does it work? If no candidate wins outright with more than 50% of first preferences, whoever is in fourth place drops out and the second preferences of their backers are reallocated to the other candidates. If there is still no winner the third placed candidate is then eliminated with their second preferences similarly reallocated. The candidate accumulating the most votes through the different rounds then wins.

She added: "We have to have our principles and policies but we also have to win the support of the public and understand why we did not get elected last time."

Ms Cooper said she was "fighting for every vote", suggesting that up to 50% of Labour members, registered supporters and affiliated supporters had yet to make up their mind.

'Clear alternative'

Insisting that the choice they made "would affect the next ten years", she told Dermot Murnaghan on Sky News that she offered a "clear alternative" to the Conservatives but also to Mr Corbyn who she said would "return Labour to the 1970s and 1980s".

"It is not enough to be angry at the world, we have to change the world," she said. "We have to have radical ideas for the future but to be credible enough to put them into practice."

She added: "There are so many people who depend on Labour and we will be letting them down if we rip this chance up."

Ms Kendall rejected media reports she was telling her supporters who to cast their second preferences for, insisting she was the candidate best placed to "beat the Tories in 2020 and move us on from where we have been over the last five to eight years".

Speaking on Andrew Marr, Chancellor George Osborne's said the momentum behind Mr Corbyn's campaign was "a symptom not the cause" of Labour's problems.

He suggested Labour had, for some time, been moving "sharply to the left" and, as a result, there was a "big responsibility" for the Conservatives to represent working people.