While lenders originally reduced rates following the drop in bank base rate to 0.50%, they subsequently increased them in the months that followed.
Borrowers with a 40% deposit looking for a £150,000 mortgage now face having to pay £45 a month more than if they had taken the same deal out six months ago.
Michelle Slade, spokesperson for Moneyfacts.co.uk commented: "While lenders have made positive steps in reducing rates, more is still needed to counteract the large increases they made in previous months.
"The cost of funding on the swap rate market is lower than it was six months ago. Borrowers will be asking why the banks are taking an increased margin for the same deal.
"The positive news for borrowers is that while rates are slowly decreasing, we are seeing signs that credit conditions are slowly easing.
"A number of lenders are increasing the LTV up to which their best deals are available, while other lenders are moving to offering higher LTVs. These include Ipswich BS, Nationwide BS, Nottingham BS, Tipton & Coseley BS and Woolwich.
"In the last month alone the number of deals available to borrowers with a 10% deposit has increased from 88 to 109, while the total number of mortgages available has moved back over the 1,800 mark for the first time since January 2009."
