Britain"s growth rate is set to double when official figures for the second quarter are released this week, reports chartered accountant Harris & Co.
Annual growth is also likely to accelerate to 1.4%, which would be the strongest for more than two years.
Finance ministers from the G20 group of nations, meeting in Moscow last week, warned that the world economy remains too weak and its recovery is still fragile.
The Office for National Statistics will release its first estimate for second-quarter GDP on Thursday this week. Economists expect output to have grown by 0 .6%, up from 0.3% in the first three months of the year. Some economists are forecasting an even higher figure.
All four headlines sectors of the economy - services, industry, construction and agriculture – are expected to have expanded in the April to June quarter, for the first time since the third quarter of 2010.
The figures will be seen as a vindication of the Chancellors strategy. The IMS, which criticised him earlier this year for not doing enough to boost the economy, this month raised its forecast for the 2013 UK growth from 0.7% to 0.9%. That is stronger than for the Economist, with Germany set to expand only by 0.4%