Stanley Gibbons, the stamps and memorabilia dealer, believes the "all-consuming passion" of collectors will continue to insulate it from the wider economic slump and attract investors from other falling classes of assets.

The Guernsey-based company today posted a 6 per cent rise in first half profit to £1.6 million on rising sales and revenue.

Stanley Gibbons reported sales of £9.8 million for its range of stamps, autographs, cards and memoribilia, doubling its ratio of online sales in 12 months to £2.37 million - 24 per cent of total sales.

Martin Bralsford, the chairman, said the price of stamps and signatures showed no correlation to shares and property prices, making the asset class an attractive alternative in the current economic downturn.

"Collecting is an all-consuming passion," he said. "That is why the prices of rare stamps and historical signatures show no correlation with the stock market, property prices and other traditional forms of investment. Historically, collectibles have increased the most in times of high inflation."

According to Stanley Gibbons, an index of rare stamps has increased by 39 per cent in 2008. "Current performance within the market for rare stamps and historical signatures demonstrates an absence of recession fears. In fact it has proved contracyclical to trends elsewhere in the world market," it said.

Mr Bralsford said the outlook was for "another strong year" for Stanley Gibbons. He said the company would contiinue to seek partners to build business in stamp-loving Asia.