Gibraltar-based PartyGaming launched its PartyPoker website eight years ago. At its busiest, it has 65,000 customers playing in games involving eight players, such as Texas Hold'em.

The site lures players with promises of giant prizes. Entrants to online tournaments pay as little as $32 (£17) for the chance to grab a place at a $2m tournament on a luxury cruise liner.

Its success mirrors the huge growth in online poker in Britain, which has alarmed pressure groups already upset by changes to gambling laws that could herald a wave of mega-casinos.

PartyGaming has refused to commit itself to a public listing but most City observers believe it is only a matter of time before it rubber-stamps plans for an initial public offering in September.

The company yesterday announced the appointment of Sage Group chairman Michael Jackson as non-executive chairman. Former 3i chief executive Brian Larcombe is to be non-executive deputy chairman.