A warning message attached to gambling adverts does little or nothing to reduce the amount that people bet, according to research.

Academics at the University of Warwick measured the effect of the industry’s responsible gambling slogan: “When the fun stops, stop” and found it did not show any significant effect on gambling behaviour.

They also pointed to the fact that the word fun is printed in much larger font than any other word in the message, which is meant to promote more responsible gambling.

Researchers from the university’s psychology department asked 506 people, who said they were fans of Premier League football and also had experience of sports betting, to place small wagers after viewing adverts, some of which contained the warning label and some of which did not.

They found that those who had seen the responsible gambling message bet more often than those who had not.

While the difference was not statistically significant enough to indicate conclusively that the message is counterproductive, the researchers concluded it did not achieve its aim of promoting more responsible gambling behaviour.

Gillian Wilmot, who chairs the industry’s Senet Group, which is responsible for the slogan, said it had “generated substantial awareness of the link between negative emotional states and problem gambling, giving young men an accessible phrase to challenge each other’s behaviour in a way that has now passed into popular culture. Discouraging all betting was never its purpose. Instead it aims to get gamblers to pause and reflect, in much the same way as the Bet Regret messaging.

However, she said the group was considering upgrading the warning message, including shrinking the size of the word fun.

“Last year, we initiated a review of the campaign, informed by a substantial behavioural study, and the new creative will reflect a change to the relative size of the word fun in response to feedback.”

One of the report’s authors, Dr Lukasz Walasek, said: “The purpose of the “When the fun stops, stop” warning labels is to encourage more responsible gambling behaviour. Yet there is hardly any evidence suggesting that such labels are effective.”

The slogan is likely to appear much less often on television in future after the industry introduced a voluntary ban on advertising during sports events in response to concern about the impact on children and vulnerable people.