"The whips are telling Conservative MPs today a very simple message - if they fail to vote with the government on Tuesday they will be destroying the government's negotiating position and handing control of Parliament to [Labour leader] Jeremy Corbyn. Any Conservative MP who does this will have the whip withdrawn and will not stand as Conservative candidates in an election", the source said.
On Wednesday, Johnson announced a decision to suspend Parliament for five weeks from mid-September until 14 October, thereby reducing the legislature's chances of stopping the no-deal scenario.
Meanwhile, a cross-party alliance of parliamentarians is expected to put forward a bill against the withdrawal without an agreement on Tuesday, when the legislature returns from its summer recess.
The decision to threaten defiant lawmakers with punishment was reportedly made by Johnson after a meeting with Conservative whips at his Chequers residence on Sunday.
Since January 2019, the UK Parliament has rejected the divorce deal negotiated by the Theresa May government with Brussels three times. Prime Minister Johnson has vowed to take the country out of the European Union by any means necessary by the 31 October deadline unless the bloc agrees to renegotiate the contentious deal.
