Anti-war campaigners face backlash over 'intimidatory' tactics
Several have received emails from campaigners warning them they will face a "vote of no confidence" from their local party members unless they oppose RAF airstrikes.
A demo was staged last night outside the constituency office of prominent backbencher Stella Creasy, who says she has not made up her mind yet.
Many others have received emails from Momentum, the pro-Jeremy Corbyn campaign group, warning them they face dire consequences if they back the war.
The tactics have prompted a wave of anger from Labour MPs on both sides of the debate.
People using Syria for their political ends to get rid of MPs are utter scum. You are colluding with your enemies https://t.co/uqEpwHWIPn
Protesting outside someone's home is a step too far. I will be voting against air strikes. BUT sensible arguments persuade not intimidation
Speculation is mounting that Ms Creasy, the MP for Walthamstow, could be one of those facing de-selection from hard-left activists in her constituency, prompting Shadow Chancellor to defend her today.
The deep splits within Labour burst into the open again as MPs prepare to vote tonight on whether to join the US-led coalition bombing Isil targets in Syria.
At least 30 Labour MPs are expected to defy their leader by backing military action.