Chancellor Rachel Reeves said the Iran crisis was “not our war, but it is pushing up bills for families and businesses”. The rate of Consumer Prices Index inflation rose to 3.3% in March from 3% in February.

Ms Reeves said: “This is not our war, but it is pushing up bills for families and businesses. That’s why it’s my number one priority to keep costs down.

“Our economic plan is the right one and has put us in a stronger position to support families in the face of this new crisis.”

Pointing to measures announced before the conflict, she said: “We’ve taken £117 off energy bills, frozen rail fares and protected motorists with the fuel duty freeze.

“We’re acting to protect people from unfair price rises if they occur to bring down food prices at the till, and are boosting long-term energy security — building a stronger, more secure economy.”

Sir Mel Stride MP, Shadow Chancellor of the Exchequer, accepted that the conflict in the Middle East is increasing inflation, but he warned that Labour’s choices "have made everything worse and made our economy vulnerable".

He added: “Tax hikes, reckless spending and disastrous energy policies have left Britain exposed. We already had the highest inflation in the G7 when this crisis began. We need a different approach: cutting the benefits bill, lowering taxes and drilling in the North Sea. Get Britain Working Again.”

Higher motor fuel prices were the main driver of the acceleration in inflation, rising 8.7% month-on-month – the largest increase since June 2022, shortly after the Russian invasion of Ukraine.

Office for National Statistics chief economist Grant Fitzner said: “Inflation climbed in March, largely due to increased fuel prices, which saw their largest increase for over three years.

“Air fares were another upward driver this month, alongside rising food prices.

“The only significant offset came from clothing costs, where prices rose by less than this time last year.”