Nike says the ad for John Smith's bitter, which shows the star of Phoenix Nights kicking a football and shouting "'Ave it", is too similar to its "Just Do It" slogan.

A letter sent to Scottish Courage, which makes John Smith's bitter, by Nike's solicitors Dickinson Dees describes Mr Kay as "an overweight and apparently unskilled footballer".

The letter adds his appearance is "detrimental to Nike's trademarks which are registered in the main for sports clothing, tarnishing them and making them less attractive and less distinctive.

"As a result, damage has or will be caused to Nike by your activities."

It also says the twisting of the John Smith's logo makes it look like Nike's own "swoosh" symbol.

'Perplexed'

The message then seemed to be you don't have to be a superstar to wear Nike - now it seems you can't be overweight or unskilled

John Botia, Scottish Courage

The brewery, part of Scottish and Newcastle, insists it will not drop the ad - part of a �10m campaign - and appealed to Nike to have a sense of humour.

Scottish Courage brand director John Botia added: "We're not sitting here seething - we're just a bit perplexed. Nike's reaction seems way over the top.

"They've done a pretty good job of insulting a huge chunk of their customers.

"One of the most creative ads they ever ran was the one on Hackney marshes which mixed superstars with grassroots players.

"The message then seemed to be you don't have to be a superstar to wear Nike - now it seems you can't be overweight or unskilled."

John Smith's is accused of altering its logo to look like Nike's 'swoosh'

Mr Botia also dismissed as "nonsense" the claim the promotion infringes Nike's trademark.

A Nike spokesman insisted the company enjoyed the campaign, but was just trying to protect its image.

"A small number of the media promotion campaign used a John Smith's logo altered to look like the Nike swoosh along with the words 'Just 'Ave It'," he added

"Both are clear references to Nike's own trademark.

"Nike has contacted John Smith's and we are confident this will be resolved in the near future."