Old Mutual and IAG outperform as Britain's FTSE jumps nearly 2 pct

* FTSE 100 jumps 2 pct to 6,466.00 points

* Rand's rise buoys South African-exposed Old Mutual (Other OTC: ODMTY - news) and SAB

* Traders welcome IAG's move on Aer Lingus (Other OTC: AELGF - news)

* FTSE still down 4 pct since start of 2014

By Sudip Kar-Gupta

LONDON, Dec 18 (Reuters) - Britain's main equity index enjoyed one of its best days so far this year on Thursday, as the U.S. Federal Reserve's pledge for a "patient approach" to any interest rate increase lifted stock markets around the world.

Financial services company Old Mutual and British Airways owner International Consolidated Airlines Group (IAG) were among the best performers on the blue-chip FTSE 100 index.

Old Mutual, which has major operations in South Africa, rose 5.7 percent, making it the best FTSE stock in percentage terms.

Traders said Old Mutual was being boosted by a rise in the rand currency, which rallied against the U.S. dollar after the Fed's statement. The stronger rand also lifted drinks group SAB Miller by 5.6 percent, since SAB is also present in South Africa.

IAG rose 4.5 percent. Aer Lingus rejected a takeover approach from IAG, which is keen to gain control of the Irish airline's slots at London's Heathrow Airport, but traders nevertheless welcomed IAG's ambitions.

The FTSE 100 itself closed up 2 percent at 6,466.00 points - its second-best performance in a single day since July 2013 and coming close to a 2.4 percent surge on Dec. 16 this week.

The index tracked similar gains elsewhere in global equity markets after Federal Reserve Chair Janet Yellen said on Wednesday that U.S. interest rates were unlikely to rise for "at least a couple of meetings," meaning April at the earliest.

Yellen's comments eased concerns that a tightening in U.S. monetary policy and a rising dollar could curb global economic growth.

The FTSE also flickered higher after data showed that British retail sales had surged at their fastest annual rate in more than a decade in November.

"We're now well set up for the self-fulfilling prophecy of the end-of-year rally," said Central Markets trading analyst Joe Neighbour.

The FTSE 100 hit a peak this year of 6,904.86 points in early September, its highest level since early 2000, but then lost ground in October and remains down by around 4 percent since the start of 2014. (Additional reporting By Francesco Canepa; editing by Ralph Boulton)