Britain's top share index extended gains by midday on Friday, climbing 1.9 percent, after index futures expired across markets while rallying oil prices lifted energy majors.

By 1100 GMT the FTSE 100 was up 80.08 points at 4,360.94 points and on track to post its biggest daily percentage gain since June 1 after crossing into positive territory on Thursday.

U.S. stock futures, pointed to a higher open on Wall Street, extending a rally in the previous session after upbeat U.S. manufacturing and jobs data revived hopes of a global economic recovery.

"There is a relief today that Wall Street held up and is going better," said David Morrison, market strategist at GFT Global. "Traders are looking at 4,280 holding in the near term. Possibly this is a good level of support and we might get a rally back up."

Index futures, index options and stock options expired on Friday, in a 'triple witching' that adds to market volitality.

Energy stocks gained ground as oil prices stayed above $71 a barrel. BP added 2.2 percent, BG Group surged 4 percent and Royal Dutch Shell gained 1.3 percent.

Miners recovered after recent falls, with Lonmin, BHP Billiton, Anglo American, Kazakhmys and Rio Tinto up 0.9-5.6 percent as metals prices turned positive.

Xstrata, buoyed on Thursday by a pair of broker upgrades, gained 4.1 percent after the Financial Times quoted an unnamed banker as saying commodity trader Glencore, which owns over a third of the miner, was in talks with bankers about a flotation.

Banks were in positive terrority with Barclays, Standard Chartered, Lloyds Banking Group, Royal Bank of Scotland, and HSBC gaining between 0.7 and 2 percent.

HSBC was supported by UBS, which added the stock to its Europe "Key Call List" in a strategy review.

Life insurers saw good support as well, helped by a bullish Deutsche Bank note on the sector, with the broker raising target prices across the board.

Aviva, Standard Life, Prudential, and Friends Provident added 3.8-4.8 percent.

HOUSEBUILDERS REVIVE

In a sign the British housing market could be slowly recovering, housebuilder Taylor Wimpey said it had seen stability in the past six weeks, and it might increase the number of new sites during the second half.

Taylor Wimpey shares topped the FTSE 350 leader board, up 9.7 percent, while peers Barratt Developments, Bovis Homes, Bellway, and Redrow added 2.7-8.4 percent.

Drugmakers were on the up, buoyed by strength in AstraZeneca , which rose 2.6 percent as UBS added the stock to its "First XI" list citing drug pipeline opportunities.

Peer Shire rose 1.6 percent, while GlaxoSmithKline edged up 0.4 percent.

There were few blue-chip fallers approaching midday, with just some defensive issues seeing their recent attractiveness fade as risk appetite returned.

Smith & Nephew was the top faller, shedding 0.9 percent, while J Sainsbury slipped 0.2 percent.

BAE Systems fell 0.4 percent after the firm declined to comment on a report saying Saudi Arabia may order another 72 Eurofighter jets worth around 5 billion pounds.