Rebel Labour MPs have accused the leadership of trying to bully them into line by threatening to prevent them standing at the next election.
Hilary Armstrong, the chief whip, has ordered a crackdown on backbench discipline after 49 MPs voted against anti-terror legislation to inflict the Prime Minister's first Commons defeat.
Clare Short, the former cabinet minister, said she was warned by Ms Armstrong that she had broken party rules by not telling her in writing she would vote against the Government over proposals for detaining terror suspects for up to 90 days without charge.
She said the implicit warning was that she could have the Labour whip withdrawn - and ultimately not be allowed to stand at the next election as a Labour candidate - if she did not toe the party line.
Dissident MPs, who include Glenda Jackson, Bob Marshall-Andrews and Kate Hoey, have also learnt that one constituency party is discussing a motion calling for the rebels to be expelled.
Ms Short said: "They are plotting to intimidate and frighten those who voted against. It shows the way their horrible fixing minds work. Tony Blair said he was going to learn some humility after the election, but there's little sign of it."
The House of Lords is preparing to reopen the controversy over the detention of terror suspects. Lord Foulkes of Cumnock, a former Labour minister, has tabled an amendment backing 90-day detention. Another Labour peer, Lord Sewel, has tabled an amendment supporting 60-day detention. Both proposals are likely to be put to the vote, leaving ministers with a dilemma over whether to vote against plans of which they approve.Reuse content