The Queen yesterday became the highest-profile casualty of the slump in dot.com shares when the value of her stake in a fledgling internet company fell by £157,000 in a matter of hours.

The monarch's 1.5% stake in Getmapping.com, which sells aerial photographs of Britain via the internet, was worth £912,000 shortly after the company floated on the stock market in April.

But the turbulence of the markets and the falling price of dot.com shares have seen the value of the royal investment slump by almost 80%.

Nearly half the value of the stake was lost yesterday after disappointing results from the company knocked its shares back 41p to just 51p. The holding is now worth £195,840.

Ironically, it was poor sales of a Domesday millennium map dedicated to the Queen - the product that attracted her to the firm - that triggered the problem. Yet despite the nosedive in Getmapping's share price the Queen is still sitting on a regal return on her investment. She bought a 1.5% stake in the company for £50,000 before it floated.

A spokesman for the Queen last night refused to say whether she planned to hold on to her holding or had any other dot.com investments. "We don't talk about her individual personal holdings as it would inadvertently act as a commercial endorsement," he said. "As far as the Queen having any other investments in IT or cutting-edge technology firms, I'm afraid I'm unable to comment."