The Tory party will not accept a “ghastly cabal” of pro-EU cabinet ministers stitching up a replacement for Theresa May, Iain Duncan Smith has warned.

The former Conservative leader declared war on senior ministers rumoured to be planning to topple the prime minister in favour of David Lidington, her de-facto deputy.

However, significantly, the arch-Brexiteer left open the “option” of backing Ms May’s deal if it returns for a third “meaningful vote”, for fear of a worse “alternative”.

Lashing out at media briefings of a “cabinet coup”, Mr Duncan Smith said: “I think that’s appalling, I think they should be censured and some of them should be sacked.

“And the idea of a cabal, a cabal that never wanted to leave the European Union, turning out to decide what should happen over our future would be unacceptable to my colleagues.”

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Speaking on the BBC’s Andrew Marr Show, he insisted: “If there is to be a leadership change, that leadership change has to be done through the correct process, with the membership out there deciding who will be their leader – not some ghastly five or six man and woman cabal that actually decides things internally.”

On suggestions of Mr Lidington as a stand-in leader, he said: “If the answer is a caretaker Mr Lidington, or someone else, what the hell is the question?”

The attack came as Mr Lidington attempted to stamp on the speculation, saying: “I don’t think that I’ve any wish to take over from the PM [who] I think is doing a fantastic job.

Iain Duncan Smith says Cabinet ministers should be apologising and should 'shut up, for God's sake'

“I tell you this. One thing that working closely with the prime minister does is cure you completely of any lingering shred of ambition to want to do that task.

The cabinet office minister said he was “not attracted by”, nor had time for plotting, adding: “I’ve learnt to take rumours in the papers with a bit of a pinch of salt over the years.”

Ms May has hinted she will not allow the third “meaningful vote”, after the Democratic Unionist Party read the last rites on it last Friday.

However, some Brexiteers fear “indicative votes” this week could pave the way for a softer Brexit or a longer delay to departure from the EU.

Asked if he could yet back the deal, given the opportunity, Mr Duncan Smith said: “I’m going to keep, and I recommend my colleagues do, keep their options open on this because we don’t know what’s happening this week.