December figures from the British Bankers' Association (BBA) show mortgage lending grew by £3.5bn in December 2009.
It said gross lending was inflated by borrowers pushing through purchases ahead of the end of Stamp Duty relief.
Gross mortgage lending in December was 12.5% higher than December 2008. The banks' annual growth rate of 4.6% in net mortgage lending substantially exceeds growth of 0.9% for November across the market as a whole.
Overall approvals in 2009 were 980,000, 27% lower than 2008 and the lowest since the BBA started recording the figures in 1997.
David Dooks, BBA statistics director, says: "The high street banks continued to lend substantial amounts in the weaker mortgage market of 2009 approving more than 440,000 loans for house purchase.
"Their share of gross lending went up from a historical level of about two-thirds to three-quarters, due to specialist lenders largely withdrawing from the market and building society finance contracting."
Brian Murphy, head of lending at Mortgage Advice Bureau, says: "Historically, we would see a drop off in mortgage purchases in December, but with the Stamp Duty holiday expiring at the end of the year, this has led inevitably to a lot of rushed-through house purchases to qualify for the extended zero band Stamp Duty threshold.
"What we are likely to see in January and February, is an unusually large drop off in mortgage purchases, because sales which would normally have been concluded in the first two months of this year have been pushed through in December to beat the Stamp Duty holiday deadline."
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