* Strong U.S corporate results, factory survey add support
* Energy firms and banks advance
By Harpreet Bhal
LONDON, July 15 (Reuters) - Strong U.S. corporate results and improving U.S. economic data lifted Britain's top share index by 2.6 percent to its highest close in four weeks on Wednesday.
Led by energy firms and banks, the FTSE 100 index ended up 108.78 points at 4,346.46, its third day of gains.
The UK benchmark is up 5.3 percent this week, on track for its best weekly gain in two months.
Chip maker Intel Corp maintained the positive tone of U.S. second-quarter earnings with better-than-expected results, following upbeat figures from Goldman Sachs.
The market was also buoyed by a key regional U.S. factory survey which posted its strongest reading in a year this month and data showing U.S industrial output declining at a slower pace in June.
Analysts said market direction will likely be dictated by a slew of corporate earnings from the United States this week.
"We have got a number of global giants still to report later this week and the balance of the second quarter results still remains very important," said Keith Bowman, analyst at Hargreaves Lansdown.
Energy firms added the most points to the UK index as crude oil rose to $60.85 after data showed a fall in gasoline stocks.
Tullow Oil topped the energy stock risers, up 5.1 percent as it announced its Jubilee field phase 1 development plan had been formally approved by the minister of energy in Ghana.
Cairn Energy, Royal Dutch Shell, BP and BG Group gained between 2.3 and 3.1 percent.
The FTSE 100 has clawed back almost 26 percent from an all-time low hit on March 9 but is down 2 percent for the year.
Banks were also in positive territory on Wednesday, led by a 4.8 percent gain in Barclays. The bank is considering the sale of its private equity business and will meet investment partners this week to discuss the issue, several people familiar with the matter said.
HSBC, Lloyds Banking Group, Royal Bank of Scotland and Standard Chartered added between 1.5 and 4 percent.
Higher metals prices lifted mining firms with Fresnillo, Kazakhmys, Eurasian Natural Resources, Lonmin and Xstrata rising between 2.6 and 5.6 percent.
Rio Tinto gained 4.2 percent after the company said iron ore output in the second quarter was up 8 percent on a year earlier.
UNEMPLOYMENT RISES
British unemployment hit its highest rate since January 2007 in the three months to May, although the number of people claiming jobless benefit rose by much less than expected last month, the Office of National Statistics said.
On a more positive note for the UK economy, Land Securities , the UK real estate company, said it was preparing for new buys in the battered UK commercial property market. It added 4.5 percent.
RSA Insurance was up 2.1 percent, with traders citing talk of bid interest from Generali.
Prudential, Aviva, Legal & General and Old Mutual gained between 5.3 and 7.4 percent.
ICAP, the world's largest interdealer broker, was one of only two stocks in the red, down 2.9 percent after going ex-dividend. Falls were tempered, however, as it posted a 10 percent rise in revenue for the period between April and June.
Reckitt Benckiser was another loser, off 0.3 percent. (Editing by David Cowell)