Shares in UK gambling companies have plunged in value by hundreds of millions of pounds after the industry regulator said it would consider slashing the maximum allowable stake on online casino games to £2.

The UK Gambling Commission’s chief executive, Neil McArthur, told a cross-parliamentary group of MPs investigating the harm caused by betting that it would consider their proposal to cut stakes over the next six months.

When markets learned of his comments on Thursday morning, investors in bookmakers and online casino firms staged a sell-off. William Hill fell nearly eight per cent, while Ladbrokes Coral’s owner, GVC, and the gambling software firm Playtech were both down sevenper cent. Rivals such as Flutter and 888 fell by smaller amounts.