A crackdown by the US authorities on internet gambling sent a shudder through shares in the sector today.
The heavy falls for companies such as PartyPoker-owner PartyGaming and 888 Holdings followed charges against the boss and founder of BetonSports.
The wider market was also under pressure after a surprise hike in inflation raised fears of a sooner-than-expected hike in interest rates.
The FTSE 100 Index had been trading flat in the opening hour, before slipping to stand 27.3 points lower at 5673.7 by mid-morning.
Increasing tension in the Middle East also put pressure on the market, leaving investors to seek out safer stocks.
Utility firms did well, with Yorkshire Water owner Kelda topping the leader board, rising 28.5p to 838p, while Severn Trent was up 31p to 1225p and Scottish and Southern Energy increased 24p to 1172p.
Tobacco companies were another safe haven with British American Tobacco ahead 21p at 1371p and Gallaher 3.5p stronger at 852.5p.
Also among the top risers was British Airways, which stood 4p higher at 348p as the company prepared to stage its AGM.
While shares in BetonSports were suspended because of the crisis, PartyPoker owner PartyGaming fell 9p, or 9%, to 94p and 888 Holdings dropped 23.25p to 169.75p in the second tier.
Elsewhere, BSkyB’s launch of broadband failed to excite investors, even though it caused Carphone Warehouse to fall 10p to 265.5p. Analysts said BSkyB’s plans looked expensive as shares fell 4% or 22p to 519p.
Outside the top flight, HMV shares were up 3%, or 4.5p to 163.25p as investors reacted positively to the appointment of Simon Fox as chief executive.
Furniture superstore MFI dropped 1.75p to 98p after a broker cut its target price for the stock.