Lack of choice and boring options are key frustrations when eating out, they say.

Nearly a quarter (23 per cent) of UK adults follow a diet that restricts certain food groups – with one in five citing an allergy to at least one food type, according to the findings revealed in CGA's Food Insights 19 report.

Vegan choices when eating in pubs and restaurants are perceived to be particularly poor, according to the research.

While only four per cent of consumers are following a strict vegan diet, 20 per cent are following a meat-free, or partially meat-free diet.

Lack of imagination in vegan dishes is mentioned by 43 per cent as their biggest frustration when eating out, followed by lack of understanding (38 per cent). Some 40 per cent complain of not having enough choice.

The vast majority (86 per cent) of vegan consumers believe it's important that there's a specially created vegan dish on the menu, rather than something that has been adapted from a non-vegan dish, the research shows.

"It's clear from our research that meat, fish and dairy reduction is becoming more prevalent – consumer consciousness is increasing both from an ethical and health perspective and it's important that pub and restaurant operators cater effectively for this growing demand," commented CGA's client director, food & retail, Fiona Speakman.

"Offering innovative dishes which cater for vegan diets will broaden the appeal of a menu and give vegan, and would-be vegan consumers additional choice and increased engagement."