Chelsea supporters have expressed overwhelming opposition to a proposed shirt sponsorship with an online casino that hails itself as a “worldwide leader in crypto gambling”.

With its deal with the mobile phone company Three expiring, the club had hoped to sign a lucrative deal with the American streaming service Paramount+ but that has been blocked by the Premier League owing to concerns about upsetting TV rights holders.

Chelsea are reportedly in advanced talks for a one-year shirt sponsorship with Stake.com, despite the forthcoming ban on gambling shirt sponsorship which begins at the end of the 2025-26 season.

A survey of fans conducted by the Chelsea Supporters’ Trust has found that 77% disagree or strongly disagree with the proposed deal with Stake.

In a statement, the CST warned that such a sponsorship would make a “total mockery” of the good work that the Chelsea Foundation had pioneered on gambling harm awareness workshops in schools in west London. “It would be short-sighted and would force many of our members to see any future CFC Foundation projects as tokenistic,” it said.

The CST asked the club’s board to commit an open dialogue over any decision, saying: “It is public knowledge that the sponsorship with Three was due to expire this summer. The CST is disheartened and unsure as to why it has taken until June to reportedly establish this new sponsor. An online casino and betting company as the primary shirt sponsor is not in line with the commitment of growing Chelsea FC as a ‘world class’ organisation.

“We understand Chelsea’s desire to maximise revenue streams across the whole club. Whilst we accept that it will happen, it must not take place at the expense of the club’s values.”

Stake’s UK website, which has a banner saying that it is the “main partner of Everton”, is a typical betting platform with a sportsbook and online casino. From outside the UK, users can also use Stake to bet in bitcoin and other cryptocurrencies. “Stake.com is a worldwide leader in crypto gambling with one of the best casino and sports betting platforms for bitcoin and other cryptocurrencies,” its global website claims.

Chelsea told the Guardian it had not finalised a deal with any brand.