William Hill has warned that new Government regulations relating to fixed-odds betting terminals will leave the company at risk of a foreign takeover and jeopardise 20,000 British jobs.
In a strongly worded letter, the bookmaker's chairman, Roger Devlin, rebuked Culture Secretary Matt Hancock for making a "catastrophic" decision.
"The jobs of around 20,000 people are at risk if the decision is made to cut ... gaming machine stakes to £2.
"Consolidation within our sector continues and I would also not want to see the impact of a disproportionate triennial outcome being a factor in the name of William Hill being added to the list of companies now in foreign ownership," he said.
It comes as Mr Hancock is thought to be poised to cut the maximum stake for fixed-odds betting terminals (FOBTs) to £2, a move the industry expects will have a devastating impact on profits.
The recommendations of a review carried out by the gambling regulator earlier this year said the maximum stake for FOBTs - which have been described as the "crack cocaine" of gambling - should be set at or below £30.
But the Government is widely expected to follow advice from campaigners for a more drastic reduction to £2.
A final announcement on the change is due this week.
Mr Devlin pointed out that pressing ahead with the £2 limit will see £1 billion "forfeited to the Treasury at a time when funding of public services is under considerable pressure".
He added: "At William Hill, we have a long and proud commitment to the UK and I do not want this to change."
The chairman is also calling for a meeting with Mr Hancock.