Three former British cabinet ministers are set to warn that a renegotiated Iran nuclear deal would destabilize the Middle East, in a warning shot to government support for the agreement.

Former Defence Secretary Liam Fox, former Communities Secretary Robert Jenrick, and former Welsh Secretary Stephen Crabb are all backing a motion to be debated in Parliament that lists a string of proposed changes to the draft they say will impede Tehran’s drive towards nuclear weapons.

The changes include introduction of a stricter monitoring regime of Iranian nuclear activity and taking a tougher approach to policing Iran’s “destabilizing” activities.

The motion to be debated today states: “This House expresses grave concern at the imminent prospect of a nuclear armed Iran; calls on the Government in its ongoing negotiations in respect of the Joint Comprehensive Plan of Action agreement to seek to extend the sunset clauses, enact a stricter monitoring regime, retain terrorist proscriptions, and expand its scope to include Iran’s other destabilising activities in the region.”

The Tory MPs and supporters from opposition parties Labour and the Liberal Democrats are understood to be concerned by the current reworked agreement, which remains subject to negotiations, and is looking to replace the 2015 deal that the US withdrew from under former President Donald Trump.

That original Iran nuclear deal, termed the Joint Comprehensive Plan of Action (JCPOA), was signed with the UK, the US, China, France, Germany, Russia and the EU, and saw Tehran agree to curb its nuclear development in return for the lifting of economic sanctions.

Speaking to The Telegraph, Jenrick said: “The JCPOA was an inadequate response to Iran’s nuclear programme back in 2015. Why would we return to the deal when it has singularly failed to curtail Iran’s uranium enrichment?

“At this critical juncture, the West urgently needs to change tack in its strategy. Weakly tolerating Iran’s aggression and flagrant breaches out of fear of talks collapsing has led us down a dangerous path. It is time for a more robust approach, reimposing snapback sanctions on Iran and tightening the economic screw until Iran is willing to countenance serious proposals.”

He added: “The UK should follow in the footsteps of the US and proscribe the Iranian revolutionary guards corps a terrorist organisation.”