The Co-operative Bank and Britannia have seen a 31% increase in mortgage applications in the first half of the year.
There has also been a 13% increase in the proportion of customers who are remortgaging.
Neville Richardson, chief executive of The Co-operative Financial Services, said: “Our significant rise in mortgage applications has largely occurred over the past couple of months and in part reflects the range of best-buy mortgage applications we’ve been able to maintain over the period.