Britain is now “involved” in the US-Iran war and “shouldn’t be surprised” Tehran has retaliated, a former defence chief has warned after two ballistic missiles were fired at the US-UK Diego Garcia military base.

The UK hit back and accused Iran of “reckless attacks” that were a threat to British interests and allies, as it said RAF jets and other UK military assets were continuing to “defend our people and personnel in the region”.

On Friday night the UK gave Donald Trump the green light to use British bases to strike Iranian missile sites targeting the Strait of Hormuz.

Downing Street said any such action would still amount to “collective self-defence”, insisting it would not mean the UK was drawn into the wider conflict.

Iran reacted angrily to the announcement, with foreign minister Abbas Araghchi saying it would “exercise its right to self-defence”.

Posting on X, formerly Twitter, he said that the “vast majority of the British People do not want any part in the Israel-US war of choice on Iran. Ignoring his own People, Mr Starmer is putting British lives in danger by allowing UK bases to be used for aggression against Iran.Iran will exercise its right to self-defence.”

General Sir Richard Barrons, the former head of the Joint Forces Command, said “we may not have wanted to get involved but now we are involved.”

Sir Richard told the BBC’s Today programme: “Iran and the UK have been at odds for a very long time … (They) regard the UK as an enemy, so if you are seen to participate in some fashion with this US-Israeli offensive action then they are clearly going to respond. We should not be surprised by that”.

It is understood that Iran’s unsuccessful targeting of Diego Garcia was before the UK updated how the US can use the bases.

But it came after a previous warning from Iran that the UK was in the firing line.

General Sir Richard Barrons, the former head of the Joint Forces Command, said “we may not have wanted to get involved but now we are involved.”

Sir Richard told the BBC’s Today programme: “Iran and the UK have been at odds for a very long time … (They) regard the UK as an enemy, so if you are seen to participate in some fashion with this US-Israeli offensive action then they are clearly going to respond. We should not be surprised by that”.

Meanwhile, former Labour shadow chancellor John McDonnell, as well as the Greens and the Lib Dems, have called for a vote in parliament against the use of UK bases in the Iran war.

President Trump also hit out at the UK, saying it “should have acted a lot faster” in giving the US permission.

He has already piled pressure on Nato allies, calling them “cowards” for refusing to offer warships to reopen the Strait.

A Ministry of Defence spokesperson said: “Iran’s reckless attacks, lashing out across the region and holding hostage the Strait of Hormuz, are a threat to British interests and British allies.

“RAF jets and other UK military assets are continuing to defend our people and personnel in the region. This government has given permission to the US to use British bases for specific and limited defensive operations.”

This is a breaking news story, more follows…