LONDON (Reuters) - A major British manufacturing survey unexpectedly weakened in November and house price data confirmed an earlier rebound in house prices had slowed, raising questions about the strength of the economic recovery.

Most economists still expect Britain's economy will return to growth in the last three months of the year after its longest recession in at least 50 years, but yesterday's figures imply any spurt in growth — as shown in September's official industrial output data — is likely to be short-lived.

"The recovery is clearly struggling to maintain momentum, suggesting that growth next year will be pretty modest," said Vicky Redwood of Capital Economics.

Britain must hold an election by June next year, and a bounce for growth would strengthen the position of Prime Minister Gordon Brown's Labour Party, who trail the opposition Conservatives in the polls. Treasury sources have told Reuters that the government is likely to forecast growth of 1.0-1.5 percent in 2010 in a pre-Budget report due next week, the same as April's Budget forecasts.

The Bank of England also expects a solid recovery next year, though its timing is uncertain and depends on the impact of its £200 billion quantitative easing policy to pump additional stimulus into the economy.

Manufacturing activity fell last month from a near-two-year high set in October, according to the monthly PMI survey from the Chartered Institute of Purchasing and Supply and Markit.

The headline index dropped to 51.8 from 53.4 and new orders fell sharply to 53.0 from 58.0, though both measures remained above the 50-level that separates growth from contraction, where the main index has been for four of the past five months.

"It was weaker than we anticipated but then there was a surge in October, so we weren't overly surprised to get a correction in November," said Peter Dixon, economist at Commerzbank.

"It will be a long haul for the manufacturing sector and probably for the economy as a whole."

The figures point to a 0.6 percent rise in manufacturing output in the three months to November, but also that output has possibly peaked, Markit estimated.

"We may be nearing a growth peak, as the new orders to inventory ratio fell sharply," Markit economist Rob Dobson said.

The Office for National Statistics said manufacturing output grew 1.7 percent in September — its fastest monthly rate since July 2002 — after factories reopened from a longer-than-usual August break.

Growth in house prices has also slowed since the summer, the monthly survey from mortgage lender Nationwide confirmed. House prices rose by 0.5 percent in November, unchanged from October and well below monthly growth rates of one percent or higher between May and September.