LONDON—British house prices rose last month at a faster rate than expected as robust demand and a lack of new homes coming to the market kept up momentum, a survey showed on Wednesday. Mortgage lender Nationwide said house prices rose by 0.7 percent in monthly terms in October after a 0.2 percent rise in September. A Reuters poll of economists had pointed to another 0.2 percent increase. The increase left house prices 9.9 percent higher than a year previously, although this marked the weakest annual growth rate since April. Overall the survey underlined the strength of Britain’s housing market during the COVID-19 pandemic. Even the gradual withdrawal of tax breaks on property purchases over the last few months has failed to seriously dampen momentum. “We expect house prices to continue to beat expectations in the near term before a gradual rise in mortgage rates applies the brakes in the second …