English football clubs have been taking a cut of the money fans lose with the bookmaker SkyBet, the Guardian can reveal, prompting accusations that they are exploiting supporters and gambling addicts.

An internal document shows that members of the Football League (EFL), comprising the 72 clubs outside the Premier League, operated as “affiliates” for SkyBet. An affiliate is a middleman who encourages a gambler to bet with a particular company, which then pays them a percentage of the money that person goes on to lose, sometimes for the rest of their life.

The document states clubs were entitled to a “share of losses […] from accounts registered in your club name to Sky Bet through our affiliate partnership”.

The EFL said the arrangement, which lasted six years, was scrapped at the start of the 2019-20 season but admitted some clubs were still receiving funds under the “legacy” contracts and would continue cashing in until the end of the 2023‑24 season.

The Guardian understands that one League Two club made £5,000 from the deal in a year, indicating potentially much larger sums for the best‑supported Championship teams.

Campaigners and MPs condemned the relationship, called on Premier League clubs to reveal whether they have any similar deals and said the revelation should give fresh impetus to government plans to reform gambling laws.

Whitehall sources have suggested a draft white paper outlining potential reforms, put together under Boris Johnson’s leadership, could fall victim to a bonfire of regulations under the new prime minister Liz Truss. But the shadow minister for sport, Alex Davies-Jones, said the plans should not be scrapped, warning that evidence of affiliate deals “raises some serious questions about the government’s approach to gambling”.

“Despite promising much-needed reform, the government have failed to bring forward their white paper and it is people across the country who continue to be impacted,” she said. “We have an analogue approach to regulation but we live in a digital world and the government can and must do more.”

The Conservative MP Iain Duncan Smith, who has been trying to ensure the white paper is not ditched, described the arrangements uncovered by the Guardian as “terrible”. He said: “That a football club might benefit from this runs against all that they are supposed to stand for – support for their fans, for the people who go to the ground.”

SkyBet, part of the Flutter gambling empire, has sponsored the EFL for 10 seasons. Sources in the gambling world have previously alleged that clubs have affiliate deals with bookmakers, but this is thought to be the first time that hard evidence of such an arrangement has come to light.

The Labour MP Carolyn Harris, who co-chairs a cross-party parliamentary group examining gambling‑related harm, said: “This appears to be proof that football clubs are exploiting their own fans, some of whom will be gambling addicts, by taking a cut of every penny they lose to greedy bookmakers. The government must now step in to loosen the hold that the gambling industry has on the national game.”

Harris said Premier League teams should now “come clean” about whether they too have affiliate deals.

The Guardian has written previously to every Premier League club, as well as some in the Championship and Scottish Premiership, to ask whether they operate an affiliate arrangement with any gambling companies. Crystal Palace, Newcastle United, Tottenham Hotspur and Manchester United said that they did not; the remaining clubs declined to comment or did not respond.

The document seen by the Guardian appears to be an account of commercial revenues made by Accrington Stanley through EFL Digital, a division of the EFL.

It shows that the club made no revenue from acting as a betting affiliate during the fourth quarter of the 2021-22 financial year. The owner, Andy Holt, said gambling addiction was a “disaster area for society” and that he only became aware of the EFL’s affiliate arrangement this week.

James Grimes, who campaigns for an end to gambling sponsorship in football via his group The Big Step, said evidence of affiliate deals in football was “a gamechanger in the fight to end gambling sponsorship in football. No one should accept that this is normal or safe.”

An EFL spokesperson said: “When the EFL and SkyBet renewed its longstanding partnership for the 2019-20 season, we placed a greater focus on putting safer gambling at the heart of the agreement. As a result, the previous affiliate scheme was discontinued.

“While some clubs do receive revenue from legacy sign‑ups that occurred prior to the new agreement, the affiliate scheme in place was phased out and all sign‑up links via EFL Digital channels have been removed.”

SkyBet said its partnership with the EFL was modified in 2019-20 “with a clear focus on safer gambling and engaging fans responsibly”, adding: “We are committed to safer gambling – for instance becoming the first operator to introduce strict limits on under 25s – and are supportive of evidence-led measures being introduced as part of the upcoming gambling act review.”