Chief executive Ralph Topping hit out at "unfair pressure" on the business due to competición on from offshore operators and betting exchanges like Betfair - allowing punters to act as bookmakers - which work under a more favourable tax regime.
He warned: "Betting exchanges - and particularly Betfair as the dominant market player - have fundamentally changed the structure of the UK betting market. This has been exacerbated by competition from offshore telephone operators and the previous government's inertia over the issue of creating a level tax and regulatory playing field."
William Hill's telephone betting business lost us$ 2.7 million last year and is expected to make a small operating loss for the first half of 2010. The business currently pays 15 % gross profits tax and a 10 % horseracing levy on its takings - but has hit out at major players "laying" huge volumes of wagers on betting exchanges, effectively trading as bookmakers but without paying the same charges.
Topping said changes to the industry need to be backed up by "firm government action" to create a more even playing field.