* FTSE 100 down 0.5 pct at close
* Banks buoyant, hit 4-month high
* HSBC near 4-year high on MS upgrade
* Rate-sensitive stocks weigh
* Sky jumps after Fox bid to be probed (Recasts, adds detail and updates prices at close)
LONDON, June 29 (Reuters) - Robust bank and mining stocks helped Britain's FTSE 100 index outpace European peers on Thursday, caught up in a broad slide driven by concerns over central banks potentially tightening policy.
Britain's main share index ended 0.5 percent lower, having spent much of the session in positive territory, while euro zone stocks fell 1.7 percent.
British banks, a sector which would benefit from higher rates, jumped 2.7 percent to a four-month high after the U.S. regulator approved higher dividends and buybacks, sending a ripple effect across financial stocks worldwide.
The Fed approved plans from the 34 largest U.S. banks, including U.S. units of HSBC and Deutsche Bank, to use extra capital for stock buybacks and other purposes beyond a cushion against possible catastrophe.
HSBC was up more than 4 percent to a near four-year high, also boosted by a Morgan Stanley upgrade to 'overweight'. Analysts said they saw capital return rising up the agenda for the bank, with around $45 billion of surplus by 2019.
"Our work suggests HSBC will be in the top quartile of EU banks for cash returns over the next three years," said Morgan Stanley analysts.
"HSBC's weighting towards Asia sets it apart from everything else that's listed here. I can see why there's potential for a split where people start looking at HSBC instead of Lloyds, who are far more exposed to Brexit risks," said Gareth Burchell, partner at Shard Capital.
"HSBC pays a very high dividend which is also attractive."
Miners Rio Tinto, Glencore, Antofagasta and Anglo American also lent support as copper and gold prices climbed against the weaker dollar.
Shares in broadcaster Sky rose 3.3 percent after the UK government said that it intended to subject Rupert Murdoch's takeover of the group to an in-depth investigation after finding the $15 billion deal risked giving the media mogul too much power over the news agenda.
Sky's shares rose on hopes a full investigation could still be averted by concessions over its 24-hour TV news channel.
While the sell-off was broad-based, consumer staples were the biggest weight, with British American Tobacco, Unilever, Reckitt Benckiser and Diageo coming under pressure following more hawkish signals from central banks, including the Bank of England on Wednesday.
The dividends of such interest-rate sensitive stocks look less attractive when rates are expected to rise.
Mid-caps also saw some robust company moves, with hefty losses from JD Sports sending the index down 0.7 percent.
Packaging company DS Smith jumped 8.4 percent, hitting an all-time high after reporting upbeat full-year results and a planned $920 million acquisition of 80 percent of U.S. corrugated packaging firm Interstate Resources.
JD Sports sank 8.5 percent, its worst day in a year, after a trading update showed sales growth in line with expectations. (Reporting by Kit Rees and Helen Reid; editing by John Stonestreet)