Research from Defaqto shows that while the number of mortgage products available has increased to 2,948 from only 1,686 in July 2009, over 25% of the mortgages available today are restricted to lenders’ existing customers.

Kevin Bray, insight analyst for banking at Defaqto, said: “While it is no surprise to see that almost 10% of mortgages are restricted to lenders’ existing mortgage borrowers