The bookmakers would all move offshore - as such the only ones who would really suffer would be Coral, Ladbrokes, Hills, Betfred who have a major high-street presence, this would result in major job losses in addition to the closure of call-centres in London, Leeds, Sheffield, Liverpool, Warrington (might already have closed), Harrogate etc.
Joe Public could still bet with the Tote but anyone else could bet with an "overseas" bookmaker - ie. VC, Stan James, Hills in Gibraltar or one of the Malta or Channel Islands firms providing the government didn't outlaw access to such sites. The real loser is the every day punter in the high street - the real winner would be the bookmakers since they could take all their cash overseas and wouldn't have to give a penny back to British racing.
They already give a sizable proportion of ALL profits (as far as i'm aware) to British racing - of which I suspect a fair amount would come from betting on Premiership football.