* FTSE 100 up 0.5 percent, still down 4.4 percent in March
* Energy stocks gain as crude rises
* Resistance around bottom of February trading range
By Simon Falush
LONDON, March 18 (Reuters) - Britain's top shares rose on Friday as currency intervention by the world's top central banks helped lessen anxiety on the outlook for the global economy, but technical resistance was seen limiting a recovery.
By 1202 GMT, the FTSE 100 was up 28.35 points, or 0.5 percent, at 5,724.46, after it closed 1.8 percent up on Thursday.
However, the index is still down 4.4 percent so far this month, having been hammered earlier this week by concerns that leaks at a nuclear power plant hit by a massive earthquake and tsunami in Japan were out of control.
Energy stocks drove a large proportion of the gains after Brent crude oil rose 1 percent to $116 a barrel on fears of spiraling violence across the Arab world. BP added 1.2 percent on high volumes.
Companies which service energy firms also benefited, with Petrofac rising 2.2 percent. Peer Amec added 2.6 percent, also supported by Investec Securities initiating it with a "buy" rating.
Electricity grid operator National Grid added 2.7 percent after Credit Suisse raised its recommendation on energy utilities to "overweight" from "underweight", saying they will benefit from higher energy prices.
Japan bought billions of dollars to restrain a soaring yen on Friday, backed up by action by European central banks as the world's richest nations moved to calm financial markets made nervous by Japan's nuclear crisis.
This seemed to reassure investors that authorities were determined to protect the global economy, but the prospect of increased violence in Libya after the United Nations authorised military strikes to curb leader Muammar Gaddafi, kept investors cautious.
Meanwhile, the Arabian gulf was also a source of anxiety with hundreds of Bahrainis gathered on Friday to bury an activist killed in a crackdown on mainly Shi'ite Muslim protesters that has angered Iran and raised tension in the world's largest oil-exporting region.
These factors meant investors were unlikely to rush back into equities, with some saying they still look expensive.
"People had become over-confident, we were due a correction on valuation grounds and the events in North Africa, Japan and Bahrain are just triggers for selling," said Charles Morris, manager of the $2.5 billion HSBC Absolute Return fund.
VOLUMES, VOLATLITY HIGH
Volumes were relatively high and moves in some stocks saw rapid and quite big moves because of quadruple witching, the expiry and settlement of March stock index futures, single-stock futures, equity options and stock index options.
Technical analysts said that the FTSE 100 was bouncing of oversold levels but there was some way to go before it is clear that the phase of weakness is over.
"We are unwinding an oversold situation, but until we recover to the February range lows of 5,860, it will look more like a corrective bounce, than that the correction is over," said Phil Roberts, chief European technical strategist at Barclays Capital.
Domestic data also added an element of caution.
British consumer confidence fell in February to its lowest since records began in 2004, a survey from Nationwide showed, fuelling doubts about the strength of economic recovery.
"It's actually shifting a bit of focus back to the UK after a week of global macro (news flow)," said Joe Rundle, head of trading at ETX Capital.
Retailers Marks & Spencer and Next both fell 0.7 percent, also weighed down by a note from BofA Merrill Lynch which cut its ratings on both. (Additional reporting by Tricia Wright and David Brett; Editing by Jon Loades-Carter)