Iran’s supreme leader Ayatollah Ali Khamenei has repeated a threat against the UK after it seized a VLCC allegedly carrying Iranian crude.

The 301,000-dwt Ukrainian-owned Grace 1 (built 1997) remains under detention in Gibraltar.

“Evil Britain commits piracy and steals our ship ... and gives it a legal appearance," Reuters reported him as saying.

"The Islamic Republic ... will not leave this wickedness unanswered and will respond to it at an appropriate time and place.”

The UK government responded by saying: “Escalation in the Gulf is not in anyone’s interests and we have repeatedly stressed that to the Iranians.”