The operator has added "proud sponsors of the New York Jets" on its website, despite no official announcement from the NFL team.

The deal was clear for all Jets fans to see, too, with bright orange 888.com banners on display outside the MetLife Stadium on Sunday.

There was no mention of 888’s sportsbook on the banners, which would be a violation of the NFL’s policy. However, 888.com's homepage clearly displays an image of a football player, alongside a direct link to its sportsbook.

NFL rules forbid any advertising of sports betting sites due to concerns over the spread of problem gambling, especially among the younger generation.

Yet 888 and the Jets may have found a loophole, which could be a growing concern for the NFL further down the line.

The NFL reversed a ban on casino advertising this season; so far, officials at the Jets, NFL and 888 have all declined to comment on the sponsorship deal.