Momentum is asking Labour candidates to swear loyalty to Jeremy Corbyn if they want the backing of the pressure group.
The far-Left organisation offers its support to would-be Labour MPs who sign up to the political objectives set out in its constitution.
Several contenders to be Labour candidates in marginal seats are understood to have signed the contract, according to reports.
But Labour MPs described the practice as ‘Stalinist’ and said that the so-called ‘accord’ had ‘worrying implications for democracy’.
Momentum is asking Labour candidates to swear loyalty to Jeremy Corbyn (pictured) if they want the backing of the pressure group
The 13-point contract asks would-be Labour MPs to back the Labour leader’s objectives and party manifesto to win the group’s support.
It asks them to ‘work to ensure the Labour manifesto (subject to future policy development) is fully implemented once Labour are in government’.
Included in the contract is the commitment to ‘revitalise the Labour Party by building on the values, energy and enthusiasm of the Jeremy For Leader campaign’.
There have been fears over a far-Left takeover of the party following attempts by activists to unseat candidates.
Target May with hate, says Far-Left activist
Philip May was considered a potential target of abuse by speakers at a Momentum conference, according to reports.
A university lecturer said the Prime Minister’s husband was a legitimate target as he worked for a hedge fund.
Speakers discussed launching a campaign against Mr May for June’s general election, The Sunday Times reported.
Philip May was considered a potential target of abuse by speakers at a Momentum conference, according to reports
Asked what the Left should do during the campaign, Paolo Gerbaudo, director of the centre for digital culture at King’s College London, said: ‘Make the Left hate again. The husband of Theresa May works for a £1 trillion hedge fund that is profiting from tax avoidance. So let’s take loads of hate against that man. Let’s be personal. Let’s be visceral. Let’s hate!’
Mr May works at the finance group Capital International. There is no suggestion it is involved in tax avoidance.
Another speaker, Ash Sarkar said: ‘I’m on Team Hate.’ They were speaking at an event in April called Take Back Control which was part of a Momentum festival.
A King’s spokesman said Mr Gerbaudo was at the event in a ‘personal capacity’.
Mr Gerbaudo said: ‘My point was that hate is a political emotion that has always been around and always will be and does not equate to violence.’
Last month, Claire Kober, the leader of Haringey Council in North London, fought off an attempted Left-wing coup to win reselection in her ward.
But the plot was seen as a warning that Momentum will not support candidates who do not back Mr Corbyn’s Labour vision.
One Labour MP, who asked to remain anonymous, told The Observer: ‘It reflects a Stalinist approach to politics that Momentum would come up with such a contract for candidates.
‘It has worrying implications for our democracy that there could be MPs in Parliament who have signed away their right to independent judgment.’
A spokesman for Momentum said it was ‘perfectly normal’ for Labour-affiliated groups to back candidates who ‘share their aims and values’.
He said: ‘It just makes the commitment to higher ethical standards more explicit.
You want to back candidates who are good people – who support the code of ethics.
‘We don’t have a programme. We are a campaigning organisation.
‘The accord is more a version of what every Labour member signs up to. It just spells it out a bit more.’
One candidate, Peter Chowney, leader of Hastings Borough Council, signed the contract.
He said he was unconcerned by criticism that he had signed away his independence, adding he was not ‘signing anything in blood’.
He was the Labour candidate in Hastings and Rye in June’s general election and came within 300 votes of unseating Home Secretary Amber Rudd.
The chairman of Momentum, Jon Lansman, this year forced through changes to ensure all Momentum members were also Labour members.
More recently Mr Lansman, who is running for a place on Labour’s ruling body, said he would make it easier for members to select a different parliamentary candidate.