PartyGaming was the biggest riser on the FTSE 100 index, after it emerged that members of the House of Representatives could not agree on new rules to ban internet gaming.

The new show of opposition to the plans during a debate also boosted 888, the mid-cap gaming group.

Shares in UK-listed gaming companies have come under pressure because of fears that the Internet Gambling Prohibition Act would inhibit the industry’s growth potential. A separate Bill that aims to stop Americans from using credit cards to gamble online has added to the concerns.

However, members of the House of Representatives wrangled over possible exemptions to the rules. No votes were proposed on the matter and no date to revisit the possibility of new legislation was set, raising hopes that the new plans could be grounded.

PartyGaming made 84 per cent of its revenues in America in the year to December 31.

The US Department of Justice had previously claimed that a 1961 Bill banning telephone betting extends to internet gambling, but the Internet Gambling Prohibition Act would strengthen that ruling.

PartyGaming shares ended 13p higher at 142½p. Shares in 888 increased 19p to 240p while Sportingbet added 40½p to 421p.

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