In an unexpected development, First Minister Nicola Sturgeon announced the move as she confirmed Scotland was moving to Level 0 Covid restrictions from July 19.
Under the new regime, all of Scotland’s hospitality venues – including casinos - must close their doors at midnight.
The move is particularly devastating for casinos, which do more than half their trade after 10pm.
It also provides more uncertainty for the 700 men and women employed by Scotland’s casinos, as well as further denting the £30m a year they pay in tax to the Treasury.
The decision comes despite an independent report earlier this year by Dr Lisa Ackerley, a chartered environmental health practitioner, which said casinos were “as safe, if not safer” than other hospitality venues thanks to the anti-Covid measures they have introduced.
Michael Dugher, chief executive of the Betting and Gaming Council, said: “Scottish casino operators have once again had the rug pulled from under their feet by this bizarre decision.
“The casino industry has been forced to withstand a series of inexplicable decisions by politicians within the past year and is now coming to terms with yet another setback. The brutal truth is that a curfew is disastrous for casinos and we were under the impression that a move to level 0 would see the curfew finally removed next week, but that’s no longer the case.
“The goalposts have changed time and again, which is grossly unfair on the colleagues and operators who have worked so hard to make casinos Covid-safe.
“Given that casinos do most of their business after 10pm, forcing them to close at midnight is economically self-harming and shows a complete misunderstanding of the casino industry.
“I would urge Nicola Sturgeon to re-think this decision as soon as possible, and remove the uncertainty she has placed over the hundreds of hardworking staff employed by Scottish casinos.”