Top British clubs have been urged to stop linking to betting websites from their social media channels because of the potential harm it could cause.
A group of 50 former addicts and others affected by gambling have written to 11 teams in the Premier League, EFL and Scottish Premiership.
They highlight how clubs offer match odds and links to betting sites when revealing starting line-ups on Twitter.
The adverts have also drawn criticism from some football supporters.
The letter, which has support from parliamentarians and leading clinicians, says the group is "distressed" to see this type of advertising, which is "difficult for those of us who are addicted or in recovery".
They also have fears it could influence children who use the social media site without any age controls.
The 11 clubs to whom the group has written are: Manchester City, Arsenal, Celtic, Leicester City, Newcastle United, Burnley, Watford, Norwich City, Nottingham Forest, Birmingham City and Coventry City.
The group has highlighted pre-match tweets which they claim "encourage" fans to place bets on their team and promote free bets with club gambling partners.
Premier League and English Football League (EFL) say their clubs comply with regulations, with the EFL adding its "mutually beneficial" relationship with the gambling industry is conducted in a "responsible manner".
But gambling sponsorship in football is currently being analysed as part of the government's review of the Gambling Act 2005.
Co-ordinated by charity the Big Step, the group has support from MPs Carolyn Harris, Iain Duncan Smith and Ronnie Cowan, and says clubs should "stop these practices immediately to prevent gambling harm".
The letter adds: "It's painful to see brands associated with unimaginable harm when doing something as simple as checking their team's starting line-up on Twitter.
"We hope that you will take this request seriously and we look forward to seeing your social media channels free of direct gambling promotion soon."
Manchester City and Newcastle United declined to comment when contacted by BBC Sport.
But an Arsenal spokesperson said: "Our partnership with SportsBet is founded on a joint commitment to promote safe and responsible gambling. We are pleased to partner with an industry-leading organisation that takes its social and regulatory responsibility extremely seriously.
"We would encourage anyone struggling with gambling to seek confidential and professional support at www.gamstop.co.uk."
A spokesperson for Coventry City added: "In line with English Football League guidance, the club and BoyleSports work closely to ensure that the promotion of any gambling products is conducted responsibly and in line with all appropriate licensing and regulatory guidelines.
"The club has supported Responsible Gambling Week and it's important that football clubs play their part in encouraging those fans that choose to gamble to do so in a safe way."
A Watford spokesperson said its deal was "not an endorsement of reckless behaviours" and added: "On the contrary, in fact. Sportsbet are extremely pro-active in their support of safer and more responsible attitudes towards gambling.
"Watford has for some time been in dialogue with those behind the RecoverMe app and will be continuing to support the development of the industry-specific support services they offer."
It is also understood that Norwich City promote responsible gambling as part of their deal with their betting partner.
BBC Sport has not received a response from the other five clubs.