Reality TV star Sam Gowland breached advertising rules by boasting a betting tipster service had helped him pay for his new car and linking to the site on his Instagram page, the regulator has said.

Gowland, a former Love Island contestant, told his 1.2 million followers Thebettingman website was “the way forward” if they wanted to make money, calling it the “best source of income I ever had”.

The Advertising Standards Authority (ASA) found he had failed to clearly label the post as marketing and irresponsibly promoted gambling as a means of financial security.

In a post on his Instagram story dated June 2 this year, Gowland wrote: “I told use [sic] Thursday night if u wanted to make money the betting man is the way forward for £25! 12 wins out of 14 this weekend and another winner this morning.”

He followed it with a post reading: “£450 quid up this weekend and over £1k up for the week! And that’s the reason I tell use [sic] to join.”

Gowland, who went on to appear in series 16 to 20 of MTV’s Geordie Shore, linked his posts to Thebettingman’s website with the words: “£25 to join vip group swipe up to get in the group for tonight’s bets and the rest of the weeks bets.”

He added “best second source of income I’ve ever had … hence the new car I’m getting … not bad for £25” followed by “to join vip tips group swipe up and watch the profits roll in like the rest of the members”.

In a ruling published on Wednesday, ASA found that even though it is not itself a betting site, promoting Thebettingman as an easy way to make money irresponsibly encouraged gambling.

Gowland was also 24 at the time of posting – breaching rules on featuring young people in gambling adverts.

Rules drawn up by the Gambling Commission state: “No-one who is, or seems to be, under 25 years old may be featured gambling (in marketing communications ) or playing a significant role.”

ASA also found Gowland had failed to mark the post with the hashtag #ad, or the hashtags #18+ and #gambleresponsibly.

Representatives for Thebettingman said they had not asked Gowland to post the story, but acknowledged all future posts about their product should be labelled as ads.

ASA said in its ruling that the posts must be removed in their current form and must be obviously identifiable as ads in future.

It added: “We told (Thebettingman) to ensure that their ads did not suggest that using betting tipsters was a way of achieving financial security, and not to feature a young person under 25 years of age to promote a gambling advice service.”