Welsh brewer Tiny Rebel has agreed to change the packaging of its Cwtch ale after a Portman Group ruling that it could appeal to under-18s.

A member of the public brought the packaging to the attention of Portman’s independent complaints panel after buying a 33cl of it in a Budgens convenience store.

The complaint said they initially thought it was a can of soft drink and that “it looks very similar to Sunkist”.

The complaint was upheld on two counts of contravening the Portman code on packaging and marketing alcoholic drinks, by encouraging immoderate consumption and in having appeal to under-18s.

The panel rejected two further claims that the pack – featuring a cartoon bear, bright, graffiti-style graphics and a discarded spray can – could encourage antisocial or violent behaviour and did not communicate the alcoholic nature of the product clearly enough.

In making its ruling, Portman said its panel recognised Tiny Rebel’s social responsibility work in its local community and that it had not deliberately set out to appeal to under-18s.

John Timothy, secretary of the panel, said: “I welcome the way in which Tiny Rebel has engaged with the [Portman] advisory service throughout this process and their commitment to ensure the panel ruling is incorporated into wider work to evolve the brand.

“While it was clearly not the intention of the producer to promote immoderate consumption, even indirectly, companies have to be extremely vigilant around themes that could be attractive to young people, particularly when designing 33cl cans which, in the UK, are traditionally associated with soft drinks.”

Tiny Rebel said in its submission to the panel that the colours and psychedelic pattern of the can were inspired by the Austin Powers films, while the bear was “a manifestation of the two co-founders’ personalities and a broader reflection of the industrial, urban city of Newport”, where the brewery is located.

Cwtch is only the third drinks brand to have panel rulings against it this year, following breaches by Collagin gin and Mr Gladstone’s Curious Emporium in August.

The Tiny Rebel ale brand was named Champion Beer of Britain by Camra in 2015.