Abbey has emerged as the unlikely winner in the battle for the mortgage market, as its rivals are forced to cut special offers and raise interest rates.

Market insiders believe that Abbey was responsible for one in six new mortgages in the first three months of this year. That would represent a doubling of its market share from 9% in 2006 to a current 17%.

Abbey has not been immune to the credit crunch but has access to easier funding because its parent company, Spain's Santander, can tap into European Central Bank (ECB) funds.

The ECB is widely recognised to have been quicker and more generous that the Bank of England in addressing banks' current liquidity problems.

It is still making funds available to member banks at 4%, having not been forced to cut its main interest rate at all during the credit crunch.

By contrast, the Bank of England has cut rates three times in the last five months, including last week's quarter-point cut to 5%.

But the key rate at which banks lend to each other, Libor, remains far higher - the three-month rate rose from 5.9275% to 5.9300% today.

That, argue bankers, is why UK banks have not been able to pass interest rate cuts on to many of their mortgage customers.

But foreign-owned banks, like Abbey, have been able to win new business, including that being rejected by Northern Rock now that it has been nation-alised.

HBOS is almost certainly still the country's biggest mortgage lender in the first quarter. Abbey has moved up to second place while Cheltenham & Gloucester (part of Lloyds TSB) and Nationwide battle it out for third and fourth place.