The research, carried out by affiliate betting bonus guide, Bonusfinder.com, suggests up to 30% of players are searching online for ‘unlicensed casinos’ and other black market keywords.

The Swedish market was re-regulated in January 2019, with strict requirements introduced, including gaming verticals part controlled by the state and limitations in player stakes and marketing.

It is widely thought such aggressive restrictions on licensed operators drive players away from the regulated market, to illegal alternatives.

Data from the Swedish Gambling Authority (SGA), suggests 91% of gambling is carried out by licensed operators, in a market worth more than €1.2 billion ($1.33bn); however, Bonusfinder research claims this figure is closer to 70%.

The affiliate also warned newly regulated markets, including Germany, which recently approved regulations to legalise online poker and casino from July 2021, with strict measures such as limiting slots to a €1 stake limit.

Bounusfinder Managing Director Fintan Costello said: "Instead of misguidedly declaring phase one of the Swedish legislation a 'success,' regulators should be focusing on the rising proportion of players searching for ‘unlicensed’ brands.

"Equally concerning is that newly regulated markets such as Germany appear to be ignoring their mistakes

"There is no regulated market on earth that is proposing such damaging rules and we would urge them to take heed of Sweden’s rapid plunge toward encouraging unlicensed activity."