The Building Societies Association (BSA) trade body said the UK’s 44 building societies now account for almost a third (29%) of all new mortgage lending.

Mutuals lent a total of £12.7bn of gross new mortgages in the first three months of 2015.

Net lending, the amount of new lending minus old loans being repaid, was £3.5bn. This compared with a £500m decrease for the rest of the mortgage market.

However, savings balances were hit by the launch of NS&I’s pensioner bonds. In total, savings balances dropped by £2.2 billion in the first quarter of the year.

Paul Broadhead, head of mortgage policy at the BSA, said: “Lending by building societies has been strong. Without the contribution of this section of the market the stock of mortgage loans across the UK would have shrunk in the first three months of the year.

“Societies hold a 20% share of mortgage balances, but have had a much greater share of the flow of new lending for some time. In the first quarter they delivered 29% of all new mortgages.

“This is partly because of competitive products and partly due to the more personal approach they take to underwriting. The trend looks set to continue in Q2, as around a third of mortgage approvals in Q1 were from building societies.”