One of Britain's biggest high-street lenders came under fire last night after it raised its variable mortgage rates for new borrowers in what appeared to be a pre-emptive move before tomorrow's widely expected Bank of England base rate cut.

One of Britain's biggest high-street lenders came under fire last night after it raised its variable mortgage rates for new borrowers in what appeared to be a pre-emptive move before tomorrow's widely expected Bank of England base rate cut.

Abbey said that, from today, it would increase rates on its two and three-year tracker mortgages, which automatically move up and down in line with the bank's base rate, by up to 0.5 percentage points.

The group's decision will effectively cancel out a half-point cut and would halve the impact of a one-point fall in the official cost of borrowing.

Abbey defended the increase, saying it was in response to moves made by competitors such as Northern Rock and Nationwide and adding that it continued to offer market-leading fixed rate mortgages.

However, the move did not impress Jim Sheridan, the Labour MP for Paisley and Renfrewshire North, who tabled a Commons motion yesterday calling for "fair play" from banks to pass on base rate cuts to customers. He branded Abbey's move "irresponsible".

Accepting banks had a responsibility to their shareholders, the back bencher also argued that they had one to the general public and the wellbeing of the economy.

"At this stage, it's irresponsible of banks playing hard to get. This has to be a team effort. If banks are going to behave irresponsibly and try to get one step ahead of everyone else, then that's wrong. They have to be held accountable. The public will raise questions about why they are behaving in the way they are," he added.

Earlier, Lord Mandelson, Westminster's Business Secretary, made clear the public would be "surprised and disappointed" if banks failed to pass on any cut in interest rates to their customers.

He noted how the UK Government could not force banks to pass on interest rate cuts, but said: "When official rates are being cut, it is not unreasonable for customers to see some benefit from that.

"People want to feel the benefits of that action and if it appeared that the banks were standing in the way between what the government is doing and how the public wants to benefit, then many banking customers are going to be asking some difficult questions of the banks."

Earlier this week, David Hodgkinson from HSBC said that he expected to see some "stickiness" from banks should the bank cut rates tomorrow: "Clearly, if interest rates are down significantly, the rates for borrowing will go down. But I am not going to say it is absolutely linear because it depends on the particular circumstances and the risk."

Last night, Michelle Slade from Moneyfacts, the financial services price comparison website, said: "Most lenders can't afford to pass on further cuts, so they are effectively pre-empting the next reduction."

However, a spokeswoman for Abbey explained: "Recent moves by competitors increasing tracker rates and withdrawing products has resulted in today's decision, which takes effect from Wednesday November 5.

"Despite difficult market conditions, Abbey has continued to provide competitive mortgage deals for all our customers across our range and continues to do so."

The group also announced it was withdrawing its tracker products for people borrowing 85% of their home's value. People now need at least a 25% deposit to qualify.

It is continuing to offer a five-year, fixed-rate mortgage to people with deposits of between 5% and 20%, but all other loans are now restricted to people borrowing 75% or less of their property's value.

Abbey is the latest of the major lenders to raise its tracker rates, after Nationwide increased the cost of its tracker deals by up to 0.4 points and Halifax increased its five-year trackers by up to 0.5 points.

The problem for lenders is that wholesale funding costs have remained stubbornly high despite last month's reduction in the base rate.

The key inter-bank lending rate, the three-month Libor, has only just fallen, dropping to 5.73% or 1.23% above base rate yesterday.

The bank's monetary policy committee slashed the base rate by half a percentage point to 4.5% on October 8 in an effort to stimulate the flagging UK economy.