It was also found that fixed rate deals increased in popularity during May, while the number of deals given to first time buyers also rose.
Michael Coogan, director-general of the CML, said: "The growing popularity of fixed-rate mortgages, despite the relatively high rates, suggests that many borrowers are prioritising certainty in their monthly payments.
However, he added that lending levels continued to be lower than last year.
Previous research by the CML found that gross lending in the UK during May totalled £25.5 billion.
It was found that the figure was 19 per cent lower than at the same point last year.
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