Buyers are beginning to lose the upper hand in house sales as fresh evidence suggests that in some regions of the country sellers are successfully holding out for close to the asking price.

Nearly two thirds of estate agents across the country said the difference between asking prices and selling prices narrowed sharply over the past three months, with the average buyer now paying only 11 per cent below the asking price. Sellers in East Anglia received 95 per cent of the asking price of their homes last month, although sellers in the North of England have been accepting 74 per cent of the asking price, or a £38,000 discount to their asking price, according to research by the Royal Institution of Chartered Surveyors (RICS) carried out for The Times.

Brigid O'Leary, senior economist for RICS, said: “The improvement in sentiment that has been captured in recent housing surveys is reflected in a narrowing in the gap between asking and selling prices.” Some experts attributed the narrowing margin between asking and sale prices to sellers being more realistic about pricing their homes. Lucian Cook, director of residential research at Savills, said: “More sellers now realise that their house has to be competitively priced.”

He added that sellers were growing more confident in the South of England because there were fewer properties available. “The North of England does not have the lack of stock that is affecting the South and there are many fewer cash buyers looking to purchase there, too.”

But, despite the average buyer in the North paying only 74 per cent of the asking price, 41 per cent more estate agents there said that that was an improvement compared with March.

The margin between asking and sale prices is narrowing fastest in the South East of England, with 80 per cent more agents reporting the percentage of asking prices being achieved at sale rose between March and May. However, sellers in the East Midlands are less confident, with only 10 per cent of surveyors saying that the margin between asking and selling prices has grown smaller.

However, fears are growing that the apparent swing in the housing market could be choked off as the cost of borrowing rises sharply.

Nationwide, Britain's biggest building society, raised rates on its fixed-rate deals by up to 0.86 percentage points yesterday. The interest rate on a five-year fix will jump from 4.78 per cent to 5.64 per cent despite the Bank of England base rate remaining unchanged at 0.5 per cent.

Rival lenders, including Cheltenham & Gloucester and Northern Rock, followed suit. Halifax and Abbey, Britain's biggest mortgage lenders, are preparing to increase mortgage rates next week.

There was also bad news for some homeowners as Ipswich Building Society became the first lender to announce that it would raise its standard variable rate (SVR) from 4.99 per cent to 5.49 per cent from Monday.

Millions of borrowers who have come to the end of a fixed-term deal are paying their lenders' SVR while the bank rate remains low, rather than locking in to a more expensive deal, but brokers have given warning that lenders could increase their SVRs, and that the cost of alternative fixed and variable-rate deals was likely to climb.

Richard Morea, of London & Country Mortgages, the broker, said: “It will be a bitter pill to swallow but it will be advisable to lock into a fixed-rate deal, even if it is more than their current low SVR, and the longer you leave it, the more painful that jump could be.”

Banks and building societies have blamed the rising costs of wholesale borrowing on money markets, which are used to fund lending to customers.