Britain's FTSE falls as investors brace for US, UK tightening

* FTSE 100 down 1 pct

* Oil and mining shares weigh on expectations of tighter Fed

* Property-based shares fall as BoE Carney says hike nearer

By Francesco Canepa

LONDON, Sept 25 (Reuters) - Britain's FTSE 100 fell on Thursday to a six-week low as concern that Britain and the United States will soon tighten monetary policy pulled down mining and energy stocks, as well as companies exposed to the British property market.

Shares (Berlin: DI6.BE - news) in oil major BP and global mining company BHP Billiton were among the biggest drags on the FTSE 100 , as oil and copper prices retreated on expectations that U.S. monetary policy will firm at a time of sluggish demand from emerging markets.

Dollar-priced commodities have been hit by a surge in the U.S. currency, now at a four-year high against a basket of major currencies. Investors are positioning for the end of the Federal Reserve's quantitative easing programme next month, which some feel may pave the way for future interest rate rises.

Shares in basic materials and energy companies knocked a combined 35 points off the FTSE 100, which tumbled 66.56 points, or 1 percent, to 6,639.71 points, its lowest close since Aug. 13.

"The FTSE's weighting is so tilted towards oil and mining that it skews the performance significantly," said Shai Heffetz, managing director of spreadbetting firm InterTrader. "The UK economy, however, is doing well, so I'd go for a discrete selection of stocks and sectors rather than the FTSE as a whole."

He cited British supermarkets as an example of a sector due for a recovery after its recent selloff, which has seen shares in market leader Tesco (Xetra: 852647 - news) halve in price over one year.

Britain's biggest sporting goods retailer, Sports Direct , is also betting that shares in Tesco, down 1.2 percent, will stop falling. The firm said on Thursday it has written a put option on a small stake in the embattled supermarket chain.

The FTSE 100 first extended losses in the afternoon after Governor Mark Carney said the Bank of England was getting nearer to raising interest rates.

The comment hit shares in real estate companies such as Hammerson (Other OTC: HMSNF - news) and builder Persimmon (Other OTC: PSMMF - news) , which stand to lose if higher borrowing costs puncture demand for British property.

The index's slide accelerated in late trade, mirroring sharp declines in U.S. indexes and taking the FTSE's fall over the past 4 sessions to nearly 3 percent.

Volume on the index was 50 percent above its average

(1 US dollar = 0.7853 euro) (Additional reporting by Sudip Kar-Gupta; Editing by Mark Heinrich)