BRITAIN’S ambassador to Iran has returned to London after a hardline Ayatollah demanded he be “chopped to pieces”.

The chilling outburst by one of the Iranian regime’s most senior clerics has sparked concern for Rob Macaire’s safety.

4 The ambassador has been at the centre of a diplomatic storm between Whitehall and Tehran Credit: AFP

4 Ayatollah Ahmad Alamolhoda has called for Rob Macaire to be 'chopped into pieces' Credit: AP:Associated Press

The ambassador has been at the centre of a diplomatic storm between Whitehall and Teheran since Saturday after he was arrested while attending a vigil for the downed Ukrainian airliner that killed 176 including four Brits.

In a rabble rousing speech on Tuesday, Ayatollah Ahmad Alamolhoda told hundreds of followers: “Some say the UK Ambassador must be expelled.

“Expelling the UK ambassador is the greatest act of kindness toward him. It would be a pardon.

“No. The UK Ambassador must be chopped into pieces”.

The cleric is supreme leader Ayatollah Khamenei’s representative in Mashhad, Iran’s second largest city.

The senior diplomat was also labelled “persona non grata” by Iran’s judiciary and an effigy of the envoy was burned in Tehran by hardline protesters.

The Foreign Office yesterday insisted Mr Macaire’s return to London was long-planned and he will be going back to Tehran soon after meetings with the Foreign Secretary.

In a bid to play down the blood curdling threats, an FCO spokesman said: “Ambassador Rob Macaire is returning to the UK today on a long-planned visit.

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“He will have a number of meetings while in the UK and this is very much business as usual. He will be returning to Iran in the coming days.”

The development came as Donald Trump welcomed Boris Johnson’s call for him to negotiate a new deal with the Iranian regime to stop it building a nuclear arsenal.

The US President tweeted: “Prime Minister of the United Kingdom, @BorisJohnson, stated, “We should replace the Iran deal with the Trump deal.” I agree!”

4 An effigy of the envoy was burned in Tehran by hardline protesters Credit: AFP or licensors

4 Supreme Leader Ayatollah Ali Khamenei controls the Revolutionary Guards Credit: AFP or licensors

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