LONDON (Reuters) - House prices in Britain fell for a third month running in November, according to the country's biggest mortgage lender, in a sign that the once red-hot property market is cooling fast.

HBOS Plc's Halifax index showed house prices fell 1.1 percent last month. That followed a 0.7 percent fall in October, which was revised from a 0.5 percent drop reported previously, and a 0.6 percent decrease in September. It was the steepest decline since last December.

The average price of a house slipped to £194,895.

"Coming on the back of two firmly negative prints, today's decline firmly underlines the fact that the UK housing market is shifting down a gear," said Richard McGuire, strategist at RBC Capital Markets.

The annual three-month rate of house price inflation fell to 6.3 percent from 8.9 percent in October, the lowest rate since March 2006. Annual house price growth has been in double-digits for most of this year.

The weaker than expected reading — analysts had forecast prices would be flat on the month — is likely to add to pressure on the Bank of England to cut interest rates at the end of their two-day policy meeting today.