Britain's FTSE supported by commodity stock rebound

* FTSE 100 up 0.4 pct

* Miners, oil firms rebound

* Whitbread (LSE: WTB.L - news) rises after results

* Circassia Pharmaceuticals rises after sharp slump (ADVISORY- Follow European and UK stock markets in real time on the Reuters Live Markets blog on Eikon, see cpurl://apps.cp./cms/?pageId=livemarkets)

By Kit Rees and Alistair Smout

LONDON, June 21 (Reuters) - UK shares ended higher on Tuesday with commodity stocks rebounding from early weakness, as the equities market continued to price in a greater likelihood of Britain voting to remain in the EU ahead of Thursday's referendum, despite mixed polls.

The blue chip FTSE 100 index closed up 0.4 percent at 6,189.30 points, having been down by around 0.8 percent earlier in the day.

It (Other OTC: ITGL - news) rose for a third straight session, extending gains from a 3 percent rise on Monday after polls showed momentum was shifting towards the campaign for Britain to remain in the European Union.

Two opinion polls on Monday suggested support for Britain staying in the EU had recovered some ground, though a third poll found support for a "Brexit" slightly ahead and another on Tuesday showed it drawing closer to the remain campaign.

"We have seen Brexit poll volatility, but much of the recent movement in the market looks like it is pricing in Remain," said Atif Latif, director of trading at Guardian Stockbrokers.

"This would result in a more aggressive sell off if the Leave campaign wins."

Mining stocks recovered from an early drop, with Antofagasta (LSE: ANTO.L - news) , BHP Billiton (NYSE: BBL - news) , Rio Tinto (LSE: RIO.L - news) and Glencore (Amsterdam: GX8.AS - news) all well off their lows as the price of copper rebounded.

Oil majors BP and Royal Dutch Shell (Xetra: A0ET6Q - news) both rose 0.9 percent, adding the most points to the FTSE 100. While oil fell for the first time in three days, it recovered from lows after rebels who have sabotaged Nigeria's crude exports denied a one-month ceasefire agreement.

Shares (Berlin: DI6.BE - news) in housebuilder Berkeley Group fell 1.3 percent after Canaccord Genuity (Other OTC: CCORF - news) cut its price target on the stock.

Hospitality Group Whitbread rose 1.7 percent on the back of a well-received update which showed solid figures from its Costa Coffee outlets.

"Costa Coffee continues to provide the main stimulus behind Whitbread's sales growth," Russ Mould, AJ Bell investment director, said.

Outside of the blue chips, Circassia Pharmaceuticals rebounded 6.6 percent after slumping in the previous session.

Neil Woodford, the second-biggest shareholder in Circassia (Stuttgart: 23863607.SG - news) with almost 20 percent, said on Monday after the market closed that he backed the board of Circassia Pharmaceuticals following the failure of its cat allergy treatment.

Engingeering company Senior (Other OTC: SNIRF - news) plunged over 12 percent after warning of lower revenue in the second half of this year at its Flexonics unit due to tough market conditions in the heavy truck and oil and gas sectors. (Editing by Alexandra Hudson)