Homebuyers in Sussex are paying out £12,800 more in stamp duty than a decade ago, new figures have revealed.

Every part of the county has recorded an increase in duty during the past ten years, according to a Conservative Party analysis of Government figures, but buyers in Horsham have taken the biggest hit.

A family buying an average- priced detached home in the district would have paid just £1,735 in stamp duty in 1997. By last year that figure had jumped to £14,815 - an increase of £13,080.

In Brighton and Hove, stamp duty on the average detached house has risen by £12,897 - from £1,287 to £14,184 - over the same period.

The rises are because years of soaring house prices have pushed more family homes into the 3% stamp duty bracket.

Since 2000, the 3% threshold has been set at £250,000.

Homebuyers purchasing properties worth more than £500,000 have paid 4% stamp duty.

The Tories say an increasing numbers of homes have been "sucked" into "punitive" rates of stamp duty because of Gordon Brown's refusal to increase the tax thresholds in line with house prices.

There are fears the higher rates are discouraging families from moving at a time when the housing market is already hit by the credit crunch.

The figures revealed big increases across the county.

Stamp duty on an average detached home jumped by £11,030 in Chichester, £10,801 in Mid Sussex, £9,712 in Arun, £9,561 in Wealden, £9,490 in Rother, £9,287 in Worthing, £9,084 in Lewes, £8,845 in Eastbourne, £8,539 in Crawley, £7,976 in Adur and £1,579 in Hastings.

Buying an average detached home in England would have led to a £1,170 stamp duty bill in 1997.

Today, that figure is £9,903.

A Treasury spokeswoman said: "In the 2005 Budget the then Chancellor doubled the zero-rate threshold to £120,000. In 2006, the Chancellor increased the threshold further to £125,000, exempting additional homebuyers from stamp duty.

"We understand that this is a difficult time for people looking to buy their first home, or seeking to remortgage.

Stamp duty like other taxes is kept under review by the Chancellor as part of the budget process."