Illegal operators are “aggressively” targeting UK customers and fuelling black market spend of up to £4.3bn, according to a new report commissioned by the Betting and Gaming Council (BGC).

The report by consultants Frontier Economics says £2.7bn is staked online at illegal and unregulated black market operators, with an additional £1.6bn staked in underground gambling venues also helping the unregulated market to “suck millions from sport and the Treasury.”

Indeed, up to £335m could be lost to black market gambling in the UK over the course of a five-year parliament, it says.

The government and the Gambling Commission are “sleepwalking into this issue,” BGC CEO Grainne Hurst said, adding that giving the regulator more powers to tackle the black market through enforcement is “only part of the solution.”

“The best defence against this growing illegal, gambling black market is getting the balance of regulations right,” Hurst added, rallying against calls from some for low-level affordability checks and advertising bans.

According to the research, more than one in five 18-24 year olds who bet already use the unsafe, unregulated gambling black market online, and via secure online messaging apps.

Overseas operators are targeting customers who have self-excluded from regulated operators, the report says.

Hurst said the report shows the “unnerving true scale” of the UK’s black market, adding that such sites are “making a mockery” of the rules by targeting self-excluded players.

“By failing to adhere to the stringent standards set by the Gambling Commission, unregulated operators in the unsafe black market can make bigger offers, grant customers total anonymity, and promise the freedom to gamble without any controls or safety measures, unlike BGC members,” Hurst said.

Andrew Leicester, associate director at the report’s authors Frontier Economics, said that while most gambling is done through regulated channels, the landscape is evolving “quickly” and beginning to suggest that black market gambling is “getting easier to find and access.”

“This report provides timely new evidence on the scale of the black market,” Leicester said. “Efforts to make gambling safer are important, but must avoid the risk of simply pushing more players and spend into unregulated providers who do not need to comply with regulations around safer play.”