Donald Trump has been branded an “insane grandad” as anger erupts in Britain over fears his war with Iran could derail the country’s fragile economic recovery. Labour peer Ayesha Hazarika launched a blistering attack on the US president, accusing him of having “no plan” and leaving allies scrambling to deal with the fallout.

Speaking during a fiery TV debate, she mocked Trump’s self-styled image as a wartime strongman. She said: “He thinks he’s Captain America. Right now he’s a bit like an insane grandad.” Hazarika warned the conflict had exposed a major strategic miscalculation, pointing out that around 20 per cent of the world’s oil passes through the Strait of Hormuz – a choke point she argued should have been secured before any military escalation. She added: “It did not take a strategic genius to work out Iran has got us because of energy.” The Labour peer also claimed Trump’s messaging had been erratic and contradictory, saying he had declared victory, criticised allies, demanded support and then insisted he was ahead of schedule.

“First of all, he said he’d won it,” she said. “Then he slagged us all off, then he’s asked for help. Last night he said he was ahead of schedule for his military plan. The guy is all over the place, and we are all dragged into this complete car crash.”

Her comments come as senior UK ministers are reported to be in despair about the potential economic consequences of the escalating conflict.

According to government sources cited by the Guardian, there is “deep gloom” in the Treasury and Downing Street that early signs of economic recovery have been knocked off course by the crisis.

The Treasury has already set up an “Iran board” to examine emergency options – including a possible universal bailout for energy bills if global prices remain high.

Frustration has also grown after Trump branded Britain and other NATO allies “cowards” for refusing his calls to help reopen the Strait of Hormuz, claiming it would be “so easy” to do.

Downing Street declined to respond publicly to the insult.

Ministers are also considering contingency measures to curb fuel demand, including the possibility of lowering speed limits, as fears grow of a global energy shock.

Speaking to the Guardian, one government source admitted the situation was “extremely challenging”, but they hoped Starmer would “get the credit” for resisting Trump’s war on Iran and focusing on the cost of living – and that people would see it was an international crisis.

Paul Nowak, the general secretary of the Trades Union Congress, said: “Working people must not be left to pay the price for Trumpflation.

“The government has taken the right first steps to support those hardest hit by rising energy bills. But ministers should be ready to go further to protect households and businesses from the fallout.”