UK mortgage lenders have raised interest payments and arrangement fees on a two-year loan by nearly £1,300 in just six months, with banks changing their deals as many as 19 times since January, Times Online can reveal.

Exclusive figures show that Britain's biggest lenders have increased the cost of a two-year fixed-rate mortgage by £1,271 for a £150,000 home loan, despite the UK interest rate falling from 5.5 per cent to 5 per cent since January.

On average, the total cost of a fixed-rate mortgage deal over two years has risen from £24,246 to £25,517.

Leeds Building Society has emerged as the biggest culprit, with the combined interest payments and arrangement fee rising by £3,228 over six months, increasing the total two-year cost from £22,191 to £25,419 .

Alliance & Leicester’s repayment rate and fee rose by £2,993, bringing the total two-year cost to £26,596 on a £150,000 loan.

While Britannia Building Society charges the highest costs for a two-year fixed deal, after increasing the repayment rate and fee by £2,761 since January to £26,845.

Halifax, which is owned by HBOS, has added a staggering £1,000 to its arrangement fee which has risen from £499 to £1,499.

Halifax has also made 19 changes to its mortgage deals since January, above the average rate of 10 adjustments lenders have implemented in six months. Abbey and Lloyds TSB have both made 15 changes each to their mortgage deals.

The cost of mortgages has continued to soar despite moves by the Bank of England and the Government to reduce the high cost of borrowing between banks, which lenders argue has prevented them from offering better terms to their customers.

On Monday, Woolwich, Barclays' lending arm, pulled all its two-year fixed loans from the market because of a shortage of affordable funding on the money markets.

According to Moneyfacts.co.uk, the price comparison service, the average rate on a two-year fixed-rate deal is now at a 10-year high.

A two-year fixed loan from Abbey, the UK's second biggest lender, has shot up from 5.59 per cent in January to 6.94 per cent before the lender pulled the deal completely.

Last week, Nationwide Building Society raised the rate on one of its two-year fixed loans by 0.5 percentage points to 6.95 per cent.

The increase in costs and constant alterations to deals is a blow for the millions of homeowners hoping to secure a two-year fixed-rate loan when they decide to remortgage this year.

In 2006, almost 1.5 million homeowners, or three quarters of all borrowers, took out fixed rates. The "sizeable majority" of them opted for deals lasting for just two years, according to the Council of Mortgage Lenders. The sudden rise in costs could force many borrowers into less flexible longer-term mortgage deals.

Melanie Bien, director of independent mortgage broker Savills Private Finance, said: "The escalating cost of two-year fixed-rate mortgages is bad news for borrowers. It effectively means less choice and less flexibility as they are forced into longer fixes in order to guarantee their monthly mortgage payments."