A senior Conservative MP has cast fresh doubt on Theresa May’s grip on power by claiming she “knows nothing” about aggressive threats to rebels accused of planning a fresh Brexit revolt.

Anna Soubry condemned the “macho” attempt to crush dissent – after potential rebels were told they will be seen as “supporting Jeremy Corbyn” – but insisted the Prime Minister was not behind it.

Blaming the “usual suspects”, Ms Soubry said: “I have no doubt the Prime Minister knows nothing about it.”

She urged Ms May to “take control” of what was happening in her name, to end the self-defeating attitude that pro-EU Tories were “thwarting the will of the people” in order to build a consensus.

The comments come after Cabinet ministers appeared to be making Brexit policy behind Ms May’s back, while she took a long summer holiday in Italy and Switzerland.

Last week, the Prime Minister attempted to reassert control by insisting she planned to stay in No 10 to fight the 2022 general election, but most Conservatives believe she will be gone long before then.

The sniping comes ahead of two days of debate on the European Union (Withdrawal) Bill, the vital legislation which will convert EU law into UK law ahead of 2019, before parts are junked.

Labour will vote against it next Monday and Labour backbenchers are attempting to woo Tory rebels to vote to stay in the EU single market, at least for a transitional period.

Speaking on BBC Radio 4’s Today programme, Ms Soubry said no Tory MP would vote against the Bill next week, making the threats made by party whips an “absolute nonsense”.

Brexit: the deciders Show all 8 1 / 8 Brexit: the deciders Brexit: the deciders European Union's chief Brexit negotiator, Michel Barnier Getty Brexit: the deciders French President Emmanuel Macron Getty Brexit: the deciders German Chancellor Angela Merkel Reuters Brexit: the deciders Commission President Jean-Claude Juncker EPA Brexit: the deciders The European Parliament's chief Brexit negotiator Guy Verhofstadt Getty Brexit: the deciders Britain's Prime Minister Theresa May Getty Images Brexit: the deciders Britain's Chancellor of the Exchequer, Philip Hammond PA Brexit: the deciders After the first and second appointed Brexit secretaries resigned (David Davis and Dominic Raab respectively), Stephen Barclay is currently heading up the position PA

However, Ms May insisted she and other pro-EU Conservatives would carry out their democratic duty to scrutinise legislation, put down amendments and attempt to win concessions.

“I don’t know of any Conservative member of Parliament that isn’t going to vote for this Bill at second reading,” Ms Soubry said.

“I thought we had abandoned this sort of rather bullish, macho way of doing business over Brexit.

“We lost our majority, so everything has changed, and one of the reasons I think we lost our majority was because of that rather silly, foolish, bullish attitude as I describe it.”

Ms Soubry added: “There is nothing weird, and there is certainly nothing treacherous, about putting down amendments and then speaking to them and indeed voting on them. It’s called democracy.”

Some Conservatives have suggested the threats and arm-twisting will backfire by increasing the chances of Ms May facing a leadership challenge this autumn.

If 47 Tory MPs - 15 per cent – send letters to Graham Brady, the chairman of the backbench 1922 committee, expressing no confidence in her, a contest must be called.

Damian Green, the effective deputy prime minister, ordered Tory MPs to get behind the Bill to “respect the will of the people and get the best possible deal for Britain”.