Britain's leading share index slipped on Thursday, weighed down by weakness in heavyweight energy stocks after recent gains, with investors also looking ahead to futures and options expiries.

The first quarterly futures and options expiries of the New Year on Friday should add a little spice to markets that, despite recent encouraging data on both sides of the pond, can best be described as docile, said Mike Mason, trader at Sucden Financial Private Clients.

At the close, the FTSE 100 index <.FTSE> was down 4.71 points or 0.1 percent at 5,940.72, having shed 0.2 percent in the previous session following five successive days of gains - the longest winning streak since last summer.

Volume was slightly better than of late, at 117 percent of the 90-day daily average, as investors positioned for the expiries.

Integrated oils <.FTNMX0530> were the biggest drag on the blue chip index, reversing some of the gains made in previous sessions as Brent crude fell back after recent strength.

BP shed 1.3 percent. The company said it was investigating possible impropriety after a whistleblower sent a letter making serious allegations to Chief Executive Bob Dudley.

Miners <.FTNMX1770> however, which were Wednesday's biggest casualties, enjoyed a rebound, tracking a recovery in copper prices, with Rio Tinto up 1.9 percent.

Among individual stocks, Shire was the top blue chip faller, down 3.2 percent, as the drugmaker moved to bolster its position as a supplier of specialist drugs by buying U.S. biotech firm FerroKin BioSciences for up to $325 million (206 million pounds).

Shire earlier surprised investors by pulling its U.S. application to sell Fabry disease drug Replagal because of signals from regulators that it would need to conduct further clinical trials before winning approval.

TESCO TRIPPED UP

Tesco shed 0.9 percent after it said the head of its UK business Richard Brasher is quitting, leaving question marks over its strategy following its recent profit warning.

But elsewhere in the stores sector, clothing retailer Next was a top FTSE 100 gainer, up 2.6 percent ahead of full-year results due on March 22, with UBS repeating its buy rating on the stock in a preview.

Aided by share buybacks, we believe this will be another year of double-digit growth in EPS, UBS said in a note.

Cruises operator Carnival also moved higher, adding 1.6 percent, with Silverwind Securities issuing a buy note on stock on a technicals basis.

Carnival is seen as being in a strongest bull trend within our model and the stock is now testing above a downtrend channel that has been in place since late January 2011 and will also shortly test its 20 week exponential moving average line which is found at 2,035 pence, Silverwind said in a note.

U.S. blue chips <.DJ1> were 0.3 percent higher by London's close after another batch of U.S. economic data, including February U.S. PPI numbers, and U.S. weekly jobless claims, continued to point to a slowly improving domestic economy.

The U.S. economy is showing good signs of recovery and Europe seems for the moment at least have a grip on their sovereign debt crisis. However you should never say never. There are very few people who really know what will happen around the corner, said Simon Furlong, trader at Spreadex Ltd.

(Editing by David Holmes)