More than half of mortgage lenders have failed to pass on this month’s interest rate cut in full to homeowners or to guarantee that they will.

The Bank of England cut the base rate by a quarter-point two weeks ago, but more than 30 of the 86 biggest lenders in the UK have yet to say whether they will cut their standard variable rate (SVR), according to a report from Moneysupermarket.com, the financial website.

A further 14 mortgage providers have failed to pass on the full cut to customers.

Alliance & Leicester cut its rate by 0.2 percentage points to 7.69 per cent, while Northern Rock reduced its SVR by only 0.15 percentage points to 7.69 per cent.

The reluctance to cut rates will be a blow to homeowners already struggling with higher utility bills and mortgage payments after five interest rate rises since August 2006.

Nearly 20 per cent of borrowers took out a deal pegged at or linked to their lender’s SVR last year, according to the Council of Mortgage Lenders (CML).

Experts say that banks are dragging their heels about passing on the rate cut as they struggle to cope with higher borrowing costs as a result of the credit crunch. Only 18 lenders have cut their SVR.

Melanie Bien, director at Savills Private Finance, the independent mortgage broker, said: “Lenders are struggling to improve margins on the back of the liquidity crisis and the fact that the Libor — the rate at which they borrow from each other — is much higher than the base rate.

"Not passing on the full rate reduction is an easy way of doing this.”

The delaying tactics came to light as the Royal Institution of Chartered Surveyors predicted that the number of home repossessions would soar by 50 per cent to 45,000 next year.

The CML said gross mortgage lending slumped nearly 8 per cent last month to its lowest since July 2005.

Louise Cuming, head of mortgages at Moneysupermarket, said: “It is very disappointing to see cuts of only 0.14 to 0.2 percentage points being passed on in many cases.”

At the beginning of December the average SVR was 7.57 per cent.

Despite the quarter-point rate cut, the average is now only 0.12 percentage points lower at 7.45 per cent.

Dominic Eaves, of Alliance & Leicester, said: “We look at a number of factors when deciding a new SVR, of which the base rate is only one.”

The CML said it was wrong to assume that there was a link between base rates and mortgage rates.

Sue Anderson, a spokeswoman, said: “There is a tendency to look at mortgage rates in a simplistic way. What that does is feed the idea that there is some magic correlation between the base rate and banks’ borrowing costs. There isn’t.”

However, according to the financial website Moneyfacts, the ten biggest lenders passed on the previous five base rate rises to their customers in full, and in some cases they increased their rates by more than the base rate.

Abbey raised its SVR by 0.34 per cent after the Bank of England increased the base rate by a quarter point to 5 per cent in November last year, while Alliance & Leicester raised its SVR by 0.3 percentage points after the quarter-point rise in January.