Gross mortgage lending reached £3.2bn compared to £2.1bn in the same month last year.
Mutuals took a 26% market share of gross lending in April, up from 21% in April 2012. In the year to April gross lending by mutuals was £11.0bn, up 28% on the same period in 2012.
Adrian Coles, director-general of the Building Societies Association, said: "Gross lending by building societies and other mutuals was up markedly in April - by 55% compared to the same month last year and by 28% in the first four months of the year.
“One reason for the substantial rise this month particularly is that 31 March 2012 marked the end of the stamp duty holiday for first time buyers. This generated a lull in activity in April 2012.
“Following last year's trend, mutual lenders are still delivering the majority of additional lending into the market as other providers have continued to de-leverage their balance sheets.”
Net new mortgage lending by mutuals was £0.9bn in April up from £0.2bn in the same month last year. In the first four months of the year mortgage balances at mutuals have increased by £2.8bn while balances at other lenders have fallen by £3.1bn.
Building societies and other mutual lenders approved a total of 30,651 mortgages in April, up 30% compared to the 23,617 in the same month last year.
Ben Thompson, managing director Legal & General Mortgage Club, said: “As expected gross mortgage lending by building societies has shown a healthy 55% increase since last year. Building societies have led the way with high LTV products at a time when many other lenders have shied away from these kinds of deals. Consequently mutuals have done a great deal to help grow the market via product innovation and a measured approach to assessing borrower risks. It is therefore not surprising to see them posting such strong lending figures and it is heartening to see especially at a time when the rest of the market and other lenders are clicking in to gear too.”