LONDON (Reuters) - A boom in Britain’s housing market has started to fade, dampened by new COVID-19 lockdowns and the coming expiry of a temporary tax cut for buyers, a survey showed on Thursday. The Royal Institution of Chartered Surveyors’ monthly gauge of new buyer enquiries fell in December to a seven-month low of +15% from +26% in November. The survey, based on the findings of chartered surveyors, again showed widespread reports of rising house prices: the headline house price balance fell only slightly to +65 in December - not far off a 21-year record of +67 in October. Only London showed weak house price growth, RICS said. Britain’s housing market rebounded strongly after the first COVID-19 lockdown as buyers sought bigger houses with gardens. Bank of England shows mortgage approvals in November topped 100,000 for the first time since 2007. “Although the housing market remains open for business in the midst of the latest national lockdown, there is a sense from respondents to the survey that the new restrictions will still impact on transaction activity over the coming months,” said Simon Rubinsohn, RICS chief economist. Analysts widely expect activity to cool off in 2021, slowed by the March 31 expiry of a cut to a property purchase tax - introduced last year to soften the hit to the economy from the pandemic - and a partial withdrawal of the government’s “Help to Buy” subsidy scheme for new-build homes. Still, respondents to the RICS survey thought an economic recovery from lockdown, helped by the rollout of COVID-19 vaccines, would help to keep house prices buoyant for now. Last week mortgage lender Halifax said downward pressure on house prices was likely later in 2021 as unemployment rises following the end of the government’s job protection scheme.