A number of major mortgage lenders are being slow to pass on last week's interest rate cut to their customers, it has emerged.

Just four of the UK's biggest lenders announced they would be reducing their rates in line with the drop in the Bank of England base rate on the day the Monetary Policy Committee announced it was reducing rates by a quarter of a point to 4.5 per cent.

Britain's biggest mortgage lender Halifax, as well as HSBC, Northern Rock, and Cheltenham & Gloucester, part of the Lloyds TSB group, all announced they were reducing their rates by the full 25 basis points last Thursday.

They were followed on Monday by Abbey, which also said it would be cutting its standard variable rate by a quarter of a percentage point.

But other major lenders, including the UK's biggest building society Nationwide, and Barclays, the Woolwich, the Royal Bank of Scotland group, Alliance & Leicester and Bradford & Bingley, all still had their mortgage rates under review yesterday.

The situation was broadly similar among West Midland lenders.

Among the major building societies based in the region, the West Bromwich said its mortgage rate would come down on September 1 and savings rates would be cut by the same amount on the same day.

No decision has yet been taken at the Coventry, however.

"We are reviewing the situation and taking into account both savers and borrowers," a spokeswoman said,

Christopher Martin, chief executive of the smaller Tipton & Coseley, said savings and loan rates would be cut by a quarter point on September 1.

Halifax's decision to cut its standard variable mortgage rate by the full quarter point to 6.5 per cent will save someone with an average £80,000 mortgage about £12 a month.

Homeowners with a £150,000 mortgage will see their monthly repayments fall by nearly £25, while those who are heavily mortgaged with a £200,000 loan will be more than £30 a month better off.

Banks and building societies have also been slow to announce what will happen to their savings rates following last week's cut.

Abbey has reduced the majority of its savings rates by 0.25 per cent, but all the other major lenders said they had not yet made a decision on whether or not to cut their savings rates in line with base rates, although Halifax said it would be making an announcement later this month.

However, ING Direct cut its savings rate to 4.75 per cent earlier this month in anticipation of the MPC's decision.

Cara Whitby, a senior researcher at consumer group Which?, said research carried out by the magazine found that the top 20 lenders tended to wait for between 20 and 30 days after a change in interest rates before they made changes to their own rates.

She said that while this was the case both when rates were cut and when they rose, the majority of changes in interest rates during the period it looked at had been reductions, meaning lenders benefited by delaying their decision.

"There is no excuse for not passing on the full benefit when rates go down," she said.