Sir Keir Starmer will be a “cool, calm head” guided by international law in response to the Israel-Iran crisis, a Government minister said.

Attorney General Lord Hermer is reported to have raised concerns about any potential UK involvement in the conflict beyond defending its allies, something which could limit any support for the US if Donald Trump decides to bomb Iranian nuclear sites.

Energy minister Miatta Fahnbulleh told Times Radio: “Legal advice is for the Prime Minister, and I think that’s where it will stay and you can understand why I won’t comment on that.

“But what I will say is that we have a Prime Minister who is a lawyer and a human rights lawyer, he will obviously do everything that is in accord with international law.

“No-one wants an escalation. No-one wants this to erupt into a major conflict in the region that is hugely destabilising for every country involved and for us, globally.

“So the most important role that the Prime Minister can play, and is playing, is to be that cool, calm head, to urge all partners around the negotiating table and to find a diplomatic route out of this.”