The British economy grew in line with expectations in the first quarter of the year, official data showed Thursday, offering a rare boost to Prime Minister Keir Starmer as he scrambles to stay in power.

Gross domestic product (GDP) rose 0.6% in the January-March period, up from a revised expansion of 0.2% in the final three months of last year, the Office for National Statistics (ONS) said.

It added that GDP grew 0.3% in March alone, beating analysts' expectations, despite the economic fallout from the Middle East war.

"Today's figures show the government has the right economic plan," Treasury chief Rachel Reeves said after the data release.

The economy "is in a stronger position as we deal with the costs of the war in Iran," she added. "Now is not the time to put our economic stability at risk."

The figures come as Starmer battles to face down a revolt within his Labour Party in the wake of heavy defeats in local and regional elections last week.

The elections saw strong gains for the hard-right Reform UK party and the left-wing populist Greens, at Labour's expense.

The results capped a difficult few months for Labour, which has struggled to revive Britain's economy since winning a general election in July 2024, having raised taxes in its two annual budgets.

There were signs of progress earlier in the year, with inflation easing toward the 2% target set by the Bank of England (BoE) and unemployment unexpectedly falling in February.

But rising energy prices stemming from the Middle East war, which began with U.S.-Israeli strikes on Iran on Feb. 28, have reignited inflationary pressures and threaten to derail growth.