Jeremy Corbyn has risked opening up a new rift with Labour moderates after he appeared to open the door to the mandatory reselection of the party's MPs.
The Labour leader said the party will “look at the process of selections” and that MPs should be “accountable all the time”.
His comments come after a trio of leftwingers were elected to the party's ruling National Executive Committee, tightening Mr Corbyn’s grip on the Labour machine.
It is likely to spark fears that MPs who have clashed with the leader and who are not ideologically aligned with his allies could be purged from the party.
Mandatory reselection would mean all Labour MPs having to win the support of half of their local party members to stand again in a general election.
Many in Labour believe mandatory reselection would boost democracy and make MPs more accountable to their constituents and local party members.
But critics believe it could simply be used as a tool to remove MPs who disagree with Mr Corbyn.
Paul Mason, the left-wing commentator and supporter of Mr Corbyn, recently suggested that MPs should have the threat of deselection “hanging over” them ahead of every general election.
Mr Corbyn was asked about the remark in an interview with the Guardian and he said: "Look, [we] will look at democracy within the party and look at the process of selections.
“We should all be accountable all the time. I'm accountable to my party, I'm accountable to my constituency and I'm quite comfortable with that.”
Mr Corbyn’s leadership received a boost earlier this week after the election of Jon Lansman, the founder of the Momentum campaign group, Yasmine Dar and Rachel Garnham, to the NEC.
Their election will allow the Labour leader to make major changes to the party's constitution and cement the take over of the party by the Left. The trio won nearly 200,000 votes between them out of the 315,000 cast after appealing to the grassroots Labour members who signed up to the party because of Mr Corbyn.
Mr Lansman founded and chairs the activist group Momentum, which helped secure Mr Corbyn's 2016 re-election as leader and drove Labour's advance at the 2017 general election.