The UK was not involved in the coordinated air strikes by the US and Israel against Iran.
A government spokesperson said on Saturday morning that Britain “did not want to see further escalation into regional conflict”.
Reform deputy leader Richard Tice was critical of the government’s position, claiming it had “seriously damaged” the historic “special relationship” between the UK and the US.
Last week it was reported that the British government’s legal advice had been that the then planned air attacks against Iran would be in breach of international law.
The stance could have ruled out the use of the UK air base in Diego Garcia in the Pacific, and also RAF Fairford, Gloucestershire, where America stations its fleet of heavy bombers in Europe.
Prime Minister Sir Keir Starmer was convening an emergency COBRA (Cabinet Office Briefing Room) summit on Saturday morning to consider next steps in the fast-moving conflict.
Tice, MP for Boston and Skegness said: “The US & Israel rightly aim to protect us all in the West by destroying the dangerous Iranian regime.
“Have Starmer & Labour cowardly refused to allow use of UK bases inc Diego Garcia?
“If so, they’ve seriously damaged the special relationship at a critical point in history.”
Conservative leader Kemi Badenoch backed the US and Israel as the conflict was under way.
She said: “I stand with our allies in the US and Israel as they take on the threat of the Islamic Republic of Iran and its vile regime.
"The same regime that carries out attacks on the UK and on our citizens, that seeks to build nuclear weapons that would threaten our country and that brutally repressed pro-democracy protests only months ago and murdered thousands of its own people.”
A UK government spokesperson said on Saturday morning: “Iran must never be allowed to develop a nuclear weapon and that is why we have continually supported efforts to reach a negotiated solution.
“Our immediate priority is the safety of UK nationals in the region and we will provide them with consular assistance, available 24/7.
“As part of our longstanding commitments to the security of our allies in the Middle East, we have a range of defensive capabilities in the region, which we have recently bolstered. We stand ready to protect our interests.
“We do not want to see further escalation into a wider regional conflict.”
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