Building society gross advances amounted to £4,062m in January 2007, compared to £3,174m in January 2006, while net advances were £1,241m in January 2007, versus £719m in January 2006.
Meanwhile, approvals were £4,199m in January 2007, up from £2,908m in January 2006.
Andrew Gall, BSA business economist, commented: "Building society gross lending was the highest January figure on record, as were approvals (loans agreed but not yet made). When adjusted to take in seasonal variations, gross and net advances are the highest January figures and approvals are the highest on record, for any month.
"Elsewhere there have been tentative signs of the cooling housing market. In January, Nationwide Building Society reported the lowest monthly growth in house prices for eight months. However, indications of a slowing market are not coming through in building society mortgage figures yet. This is a reflection of the strong numbers of loans promised but not processed, seen at the end of last year.
"We may continue to see robust mortgage figures in the near future, but expect these to fall back as the impact of recent rate rises feeds through."
