Nearly 40% of all William Hill betting shops are based in Scotland, with the chain employing 1790 staff north of the Border.
The bookmaker said yesterday that it would be forced to close more than 100 shops following the Chancellor's decision to increase the tax on fixed-odds betting terminals from 20 to 25%.
William Hill estimates the policy will cost it around £22 million a year, and is now planning to shed around 420 jobs to cut costs. The move is expected to affect its 109 worst-performing outlets, although it has not yet named the branches identified for closure.
Assistant general secretary John Park said: "The Chancellor's decision to make such a hike in FOBT duty was always going to affect the viability of betting shops on the margins of profitability.
"This has proved to be the case at William Hill and we would not be surprised to hear similar announcements from other operators in the near future.
"The Treasury's move on FOBTs demonstrated a lack of joined-up thinking by the Government, given it was taken while a review of FOBTs is ongoing."
Research showed £4.4 billion was waged in Scotland on FOBTs in 2013, with the highest concentrations of the machines and losses found in Glasgow.
FOBTs have been dubbed the "crack cocaine of gambling" because players can bet up to £100 every 20 seconds.