Buy-to-let mortgages accounted for 12% of new loans in the first half of this year, according to a report from the Council of Mortgage Lenders.
Buy-to-let loans represent 10% of all mortgage balances, up from 3% five years ago, despite five quarter-point interest rate rises since last August.
First-time buyers borrowed a record multiple of 3.37 times their salary in June, up from 3.22 times the year before.
Mortgages to first-time buyers in June declined to 35,600, compared with 39,800 a year ago. This figure is the lowest since June 2004, when there were 33,600 first-time buyers