National statistics: Economy shows strongest growth in four years

The 1.1 per cent advance – nearly double City expectations – was the highest since the first quarter of 2006, said the Office for National Statistics (ONS).

The gains were driven by the UK's services sector and the construction industry, although experts moved to dampen optimism over the figures.

Jonathan Loynes, chief European economist at research consultancy Capital Economics, warned output was still four per cent below pre-recession levels.

"With recent business surveys weakening and the fiscal squeeze looming, Q2 looks very likely to be the peak in terms of the pace of growth – expect a much weaker second half," he said.

Overall the UK posted year-on-year growth of 1.6 per cent between April and June, the strongest since the beginning of 2008. The 1.1 per cent advance over the quarter equalled 2006 and was last higher in 2001, the ONS added.

But a political war of words broke out over the figures as Chancellor Gorge Osborne claimed the strong private sector contribution "put beyond doubt" the coalition's decision to begin tackling the deficit immediately.

But Shadow Chancellor Alistair Darling claimed the brutal cuts planned could jeopardise the recovery and said the Government "will have to accept responsibility for the risks they are taking with the economy".

TUC general secretary Brendan Barber accused the Government of "deficit fetishism" and said: "There is now a huge risk that cuts in spending will bring the recovery to a shuddering halt."

The pound strengthened against the dollar and the euro following the figures as markets anticipated an increased chance of rate rises from their record low of 0.5 per cent.