The US economy has raced upwards to an annualised +5.7% in Q4 2009 and has shocked forecasters with the fastest growth since 2003.

This is despite the worlds biggest economy contracting by -2.4% in 2009, the biggest decline since 1946.

Christina Romer, White House economist, said: "It is important not to read too much into a single report, positive or negative, but this is the most positive news to date on the economy. There will surely be bumps in the road ahead. Nonetheless, todays report is a welcome piece of encouraging news."

The Bureau of Economic Analysis, which has released the data, emphasised that the fourth-quarter advance estimate was based on incomplete information and was subject to further revision.

Growth in the third quarter was originally estimated at an annualised rate of +3.5%, but was revised down to +2.2% after more information was received.