By Rebekah Curtis

LONDON (Reuters) - Blue-chip shares surged 2.6 percent in a global rally on Thursday, with banks soaring as better-than-expected results from JPMorgan (JPM.N: Quote, Profile, Research) calmed some concerns about the outlook for U.S. corporate profits.

In the financial sector Standard Chartered (STAN.L: Quote, Profile, Research) rose 9.2 percent, Barclays (BARC.L: Quote, Profile, Research) jumped 8.9 percent and Royal Bank of Scotland (RBS.L: Quote, Profile, Research) added 8.8 percent.

The reassuring results from JPMorgan came a day after Wells Fargo & Co's (WFC.N: Quote, Profile, Research) results catapulted U.S. financial stocks to their biggest gains in nearly two decades.

The FTSE 100 .FTSE closed up 135.7 points at 5,286.3, bouncing back after hitting a three-year low on Wednesday. The pan-European FTSEurofirst unofficially closed up 2.7 percent.

But investors remained jittery in a market still firmly in the clutches of a credit crisis. The FTSE has fallen more than 18 percent so far this year, against an average annual gain of more than 10 percent in the previous five years.

"Any form of positive news was always going to produce a knee-jerk positive reaction," said Graham Secker, an equity strategist at investment bank Morgan Stanley.

"This rally could run for a bit longer but we doubt it's the real deal...The overall fundamental outlook hasn't changed and it's still a bleak one," he added.

"This market may well move a bit higher but it's still skating on thin ice."