The UK has agreed to a US request to use British military bases for "defensive" strikes on Iranian missile sites, Sir Keir Starmer has said.

But the prime minister said the UK had learned lessons from the "mistakes of Iraq", and was not involved in the initial strikes on Iran and "will not join offensive action now".

The BBC understands the US is likely to use RAF Fairford in Gloucestershire and Diego Garcia in the Indian Ocean for strikes on Iranian missile sites.

The PM made the announcement, which the Telegraph reported US President Donald Trump said "took far too long", just hours before a British RAF base in Cyprus was hit by a drone strike on Sunday night with no casualties reported.

Investigations are under way to establish where it was fired from.

The attack at RAF Akrotiri in Cyprus took place at around midnight local time (22:00 GMT) with the MoD later saying that "minimal damage" was caused.

In a video statement released earlier on Sunday, Sir Keir said the basis of the decision to accept the US request was the "collective self-defence" of allies and protecting British lives, accusing Iran of pursuing a "scorched-earth strategy".

The prime minister added the US would use UK bases for the "specific and limited defensive purpose" of destroying Iran's missiles "at source".

He added that the move was in accordance with international law, and the UK government had published what it said was a summary of its legal advice.

Trump, in an interview with the Telegraph, said of the delay in accepting the US request: "That's probably never happened between our countries before."

He added on Sir Keir: "It sounds like he was worried about the legality."

The prime minister's official spokesman, asked about Trump's remarks, said Iran striking British interests had led to the change and he described the UK and US as "staunch allies".

Conservative leader Kemi Badenoch accused the government of being "too scared" to take a stronger stance against Iran because some Labour voters were "swayed by conflicts in the Middle East, not the British national interest".

"So we watch our prime minister and cabinet ministers squirm and obfuscate in interviews, because they cannot say what needs to be said because too many of their voters do not want to hear it."

Liberal Democrat leader Sir Ed Davey said "the UK must not be complicit in illegal military action" and demanded that MPs be given a say on allowing the US to use British bases.

It was reported last month that the British government had not given permission for the US to use UK military bases to support any potential US strikes on Iran.

Trump said it "may be necessary" for the US to use RAF Fairford and Diego Garcia for operations should Iran "decide not to make a deal".

Both bases have been used by the US in the past to conduct long-range heavy bombing missions.

Reform UK leader Nigel Farage said the decision to let the US use UK military bases was "better late than never" and described Sir Keir as "a follower, not a leader".

Green Party leader Zack Polanski condemned the move, saying Sir Keir had jumped into "yet another Middle East illegal war".

The US and Israel began attacking Iran early on Saturday, with Trump encouraging the Iranian people to remove the country's government.

The Iranian regime has responded with attacks on US assets and countries in the region with a US military presence, including Bahrain, Qatar, the United Arab Emirates, Kuwait and Iraq.

Sir Keir had said UK aircraft were "in the sky" in the Middle East as part of a defensive operation to protect its allies and citizens in the region, but said the UK "played no role" in the strikes.

On Sunday, he said British aircraft had successfully intercepted Iranian strikes, but added: "Our partners in the Gulf have asked us to do more to defend them and it's my duty to protect British lives."

He began the statement by saying it "remains the case" that the UK is "not involved in the strikes on Iran".

At least 200,000 British citizens are in the region - including residents, those on holidays and passengers in transit, Sir Keir said - and the government "will continue to do all we can to support" them.

British people, including members of the armed forces, as well as allies, were being put at "huge risk" from Iranian strikes, he said, accusing the regime of "becoming even more reckless".

Iranian strikes have "hit airports and hotels where British citizens are staying", and on Saturday "hit a military base in Bahrain, narrowly missing British personnel", Sir Keir said.

He added: "The only way to stop the threat is to destroy the missiles at source, in their storage depots, or the launchers which are used to fire the missiles.

"The United States has requested permission to use British bases for that specific and limited defensive purpose.

"We have taken the decision to accept this request to prevent Iran firing missiles across the region, killing innocent civilians, putting British lives at risk, and hitting countries that have not been involved."

The Foreign Office has asked British nationals in Bahrain, Israel, Kuwait, the Palestinian territories, Qatar and UAE to register their presence to receive updates.