THE FTSE 100 Index staged its biggest one-day rise in 15 months as global markets bounced back at the end of a volatile week which saw fears over the world economy weigh heavily on shares.

It had plunged below 6200 points for the first time since summer 2013 in the previous session but recovered some of its poise in early trading before optimism on Wall Street propelled the top-flight still higher.

The FTSE 100 closed up 114.4 points, or 1.8 per cent, at 6310.3, the largest rise in percentage terms since July 2013.

In New York, the Dow Jones Industrial Average was up by a similar degree at the time of the close in London.

The recovery, which followed a plunge driven by fears over the strength of the world economy and particularly the eurozone, was even stronger on European bourses. Germany's Dax and France's Cac 40 were each ahead by around three per cent.

Early impetus for the rally came courtesy of comments in the US on Thursday from St Louis Federal Reserve President James Bullard that the central bank should delay cutting back any economic stimulus measures. Wall Street was further boosted by strong corporate earnings from General Electric and Morgan Stanley and strong home construction data.

Remarks by Bank of England chief economist Andy Haldane that interest rates are likely to rise next summer - amid the gloomier economic picture - failed to dampen the pound.

Markets had already pushed back expectations for a first hike from February in the wake of inflation falling to a five-year low and weak earnings data, and there has even been speculation of the rise coming as late as the autumn.The pound was flat against the greenback at just under 1.61 US dollars and ahead by a cent against the single currency at just over 1.26 euros.

Oil prices, which have seen a dramatic slide recently, also picked up, with Brent crude heading above 86 US dollars a barrel after dropping to below 83 US dollars in the previous session.

It helped heavyweight Royal Dutch Shell lift 80.5p to 2240.5p and BP improve by 8.5p to 428.5p.

Exploration and production group Tullow Oil was the biggest climber on the FTSE 100, adding eight per cent, or 40.1p, to 524p with oilfield service company Petrofac just behind with a rise of seven per cent, or 72.5p, to 1060p.

Rolls-Royce was the leading faller as the deteriorating economic conditions behind the recent slump in stock markets were blamed by the engines giant for a downgrade to its sales and profits guidance in 2015. The shares fell nearly 12 per cent, or 108.5p, to close at 832p.

The biggest risers on the FTSE 100 Index were Tullow Oil, up 40.1p to 524p, Petrofac up 72.5p to 1060p and Hargreaves Lansdown up 50p to 921p. The biggest fallers were Rolls-Royce, down 108.5p to 832p, Randgold Reserves down 156p to 4224p and Fresnillo down 17p to 798p.