Kidsbeer began life as a guarana drink served at a restaurant run by 39-year-old Yuichi Asaba.

When Asaba had the brainwave of renaming the drink 'Kidsbeer', he realised that he had a hit on his hands.

He outsourced production, changed the formula to make it less sweet, and more frothy.

Starting from an initial run of 200 bottles a month of the retooled product, it soon became a runaway success.

Satoshi Tomoda, president of Kidsbeer maker Tomomasu, said: "Children copy and mimic adults.

"If you have this drink at occasions such as events and celebrations attended by kids, it makes the occasions even more entertaining."

Although popular in Japan, plans to import and promote the drink into the UK have fallen flat.

A spokesperson for industry watchdog The Portman Group said: "The way this drink is promoted, showing young people absolutely desperate for a drink, risks fostering harmful attitudes.

"Children need better education about alcohol, but this is not the way for them to learn."

However, the British Soft Drinks Association said the product should be allowed as long as the marketing is done more sensitively that in its home market.