Britain announced on Saturday it was deploying HMS Dragon, a type 45 destroyer, to the Middle East ahead of its “potential role” described as a “strictly defensive and independent” mission.

Kazem Gharibabadi, Iran’s deputy foreign minister, said warships “potentially accompanying the illegal and internationally unlawful actions” of the US “will be met with immediate decisive response”.

Earlier today, Tehran said it had sent the Washington a counterproposal to Donald Trump’s 14-point plan to end the more than two-month old war.

Tehran has proposed that the current phase of negotiations focus solely on ending the war and reopening the Strait of Hormuz, ruling out an immediate deal over the future of its nuclear programme – a major sticking point in negotiations.