Mr Corbyn launched his leadership fightback earlier today
Jeremy Corbyn has warned all Labour MPs in the UK they face a reselection fight to keep their seats, sparking fears of a cull of the moderates.
Launching his leadership fightback, the Labour leader said it was the "responsibility of every Labour MP to get behind the party".
But he threatened all his MPs would face an "open selection process" in every constituency "throughout the whole UK" when boundaries are redrawn in 2018.
It raises the prospect of a bloodbath for the moderate MPs, who will have to fight to become the Labour candidate in their constituency for the next British general election - currently set for 2020.
Because of the rise of Corbyn supporters among the membership, they face the threat of being replaced with more left-wing Labour candidates.
In the past it has been standard practice that the selection process was not open to those not already a sitting Labour MP.
However, Mr Corbyn's promise of an "open selection process" indicates that it will be opened up to other Labour members.
He said: "I say to Labour MPs quite simply this. I have been in parliament a very long time. I have seen leaders come, I have seen them go.
"I hope those that may not agree with me politically, may not even like me (personally I find that hard to believe but some people apparently don't like me) I hold out the hand of friendship to them all - because come September when this election is done and dusted there will still be a Tory government in office, there will still be grotesque levels of inequality in our society, there will still be whole parts of the country that are left behind.
"It's the job, it's the duty it's the responsibility of every Labour MP to get behind the party at that point and put it there against the Tories …"
Mr Corbyn has in the past insisted he is not looking to deselect Labour MPs but went on to say that the boundary changes would mean "there will be a full and open selection process for every constituency Labour Party throughout the whole of the UK."
He said sitting MPs would "have the opportunity to put their name forward".
Following Mr Corbyn's speech, Labour MP for Ilford South Mike Gapes, who has routinely been threatened with deselection by Mr Corbyn's supporters, tweeted:
Bring it on. Then see what happens. https://t.co/9TKLpNP5X2— Mike Gapes (@MikeGapes) July 21, 2016
It comes after Labour suspended its Brighton constituency party and annulled a vote that installed officers supportive of Mr Corbyn in key roles.
The boundary changes will reduce the number of MPs from 650 to 600. The first report on the changes will be out in the autumn and they will be implemented in 2018.
In his leadership speech Mr Corbyn pledged to tackle discrimination in the workplace, demanding big fines for employers who flouted equality rules and the publication of equality pay audits by firms with more than 21 workers.
And he said he would tackle the "five ills of 21st century Britain" - inequality, neglect, insecurity, prejudice and discrimination.
The Labour leader's first move in the leadership campaign comes after a 48-hour surge in applications to join the Labour Party to vote in the contest.
More than 183,000 people paid £25 (around €30) to apply to vote and Mr Corbyn's team claim it is "reasonable to assume" the majority of those will back him.