The rally on London’s blue chip index came off full throttle as investors awaited a flood of updates on both sides of the Atlantic.

The FTSE 100 Index clawed back early session gains, which had taken it past the 6300 mark, but still closed at a new four-and-a-half year high, up 10 points at 6294.4.

But the prospect of several key economic updates, including the latest policy decision of the US Federal Reserve, as well as the start of the UK earnings season, meant many investors remained on the sidelines.

Friday’s announcement that output shrunk by an estimated 0.3% in the final quarter of 2012 has had little impact on the FTSE 100 Index.

However, the pound continued to come under pressure after the GDP figure fuelled expectations that the UK will lose its AAA credit rating at some point this year. Sterling was at 1.17 against the euro and 1.57 versus the US dollar.

The biggest FTSE 100 risers were Barclays up 5.2p to 305.9p, Aberdeen Asset Management ahead 6.6p to 422p, Schroders 26p higher at 1942p and Standard Life up 4.3p to 350p.

The biggest FTSE 100 fallers were Evraz down 6.3p to 293.7p, GKN off 5.1p to 241.5p, Fresnillo 35p lower at 1663p and BG Group down 23.5p to 1142p.