London - Britain's top equity index rebounded from 15-month lows on Friday as concern eased over the state of the US economy.
Tullow Oil benefited from a broker upgrade.
Rolls-Royce missed the rally, slumping 12.4 percent after it warned that deteriorating economies in areas such as Europe and China meant its profits would not rise next year as it had forecast.
“All very disappointing, and we expect shares to weaken today,” said Cantor Fitzgerald analyst Andy Chambers, commenting on Rolls-Royce's warning.
The blue-chip FTSE 100 equity index, which had fallen some 5 percent in the first four days of this week to reach 15-month lows, gained 1.1 percent to 6,261.48 points going into the middle of the trading session.
Tullow Oil was the best-performing stock in percentage terms, rising 4.9 percent after Societe Generale raised its rating on Tullow to “buy” from “hold”.
The FTSE was buoyed by encouraging Thursday's US jobless claims and industrial output data, which helped world stock markets to edge up from earlier lows.
Comments from St. Louis Federal Reserve Bank President James Bullard that the Fed may keep up its bond-buying economic-stimulus programme also helped.
The FTSE 100 hit a peak of 6,904.86 points at the start of September, its highest since early 2000.
It has since lost ground and is down 7 percent since the start of 2014.
Even though many investors say the US economy looks robust, weak German data in the past two weeks has heightened concern about Europe.
Worries about Greece's plans exit an international bailout programme earlier than scheduled added to the concern.
“After hitting a key support level yesterday and bouncing off it, the FTSE is in a consolidation mode. Key resistance exists at around 6,440, so until we climb above that I'm not sure we're out of the woods,” said Jeremy Batstone-Carr, head of private client research at Charles Stanley. - Reuters