"Growth is strengthening, " Brown said.

"Growth in the second half will be stronger than in the first half."

The British economy grew 0.6% in the first quarter, in line with its long-running trend, and is expected by economists to exceed that in the second quarter that ends this month.

The Treasury is forecasting growth of 2% to 2.5% this year, and about 3% in 2006 and 2007.

Philip Shaw, the chief UK economist at Investec, said quarterly growth of 0.8% would deliver growth above his forecast range.

"In that case, growth of 3% would look more realistic . . . although, with a US slowdown, I am not sure that is achievable, " Shaw added.

The Treasury received a boost from official figures last week which showed that the British high street enjoyed its strongest growth in retail sales so far this year in May.

The volume of goods passing across shop tills rose 0.5% last month, taking the annual growth rate to 4%, the strongest rise since the great Christmas shopping spree in December.

The Office for National Statistics said that department stores had enjoyed their best three months of trading since February 2001, while clothes stores had their strongest quarter since May 2004.

It said electrical retailers had cited the World Cup for "good sales" of televisions.

Sales of electrical household goods posted annual growth of 19% in May after 23% in the previous month.

Last week, department store operator John Lewis reported a 42% annual rise in electrical goods sales from its stores in the week to 27 May, as flat-screen television sales reached a new high.

"The good numbers are, in part, related to the build-up to the World Cup, " lan Clarke, the UK economist at BNP Paribas, said. He warned that sales growth could stagnate if England failed to progress through the tournament. Luckily, they are now through to the last 16.

Malcolm Barr at JP Morgan said that even a flat reading in June would leave annual growth for the second quarter at a "boomy" 6.5%. "The current profile of retail sales data will do little to deter the Monetary Policy Committee from considering higher rates, " he added.

Bank of England governor Mervyn King said last month that the MPC was very aware of potential distortions to consumer spending as a result of the World Cup.

A separate report from the Royal Institution of Chartered Surveyors showed the strongest UK house price rises in two years in the three months to May.