Government efforts to clamp down on underage drinking smack of "stupidity and rank hypocrisy", according to the head of one of the UK's biggest pub chains.

Under the present law, publicans and staff face heavy fines if they serve underage drinkers - whether knowingly or not.

But Tim Martin, chairman of JD Wetherspoon, said the strictness with which the Government enforces the over-18s rule amounts to "displacement activity" and is exacerbating the problem.

He argued that consumption by teenagers is now far less supervised than previously when underage drinkers, accompanied by adults, were unofficially allowed to drink weak beers in pubs under the "watchful eye of the landlord".

And he accused ministers of creating by default a "vodka drinking culture" in public areas such as market squares, with the drink bought from supermarkets, often by parents.

In an article for the company magazine, Mr Martin revealed: "I myself, accompanied by my daughter of 22, was turned away from a Wetherspoon pub since my daughter had no ID."

He said: "The laws in this respect are incredibly stringent; the door staff and the bar staff were risking heavy fines should an underage person have crept in under the radar.

"In further efforts to clamp down on underage drinking, the Government is also sending in 15 or 16-year-olds who try to order drinks and are entitled to lie about their age if challenged.

"Legal action, including action to take away the relevant pub's licence, can result from the work of these agents provocateurs."

Mr Martin stressed that JD Wetherspoon did not advocate underage drinking and had a strong record in the area, but he said: "The way in which the issue is being dealt with smacks of rank hypocrisy and stupidity.

"There is not a policeman, lawyer or judge in the UK who waited to enter a pub to have a drink for the very first time at the age of 18 or over.

"Now it's far more difficult for 15 to 18-years-olds to get served in pubs, but all the parents I know purchase alcohol for their children of this age, who end up drinking it at parties, in market squares or on the beach."

And he concluded: "The result is that the consumption by teenagers is far less supervised than it ever used to be, with relatively low-alcohol drinks, such as beer, being supplemented by bottles of vodka."

In a BBC interview yesterday, Mr Martin said: "The Government is trying to crack down on underage drinking and alcohol abuse, which is correct.

"But it has heavily targeted pubs, and 50 per cent of alcohol is now consumed outside pubs. So what's happening is young people are finding it harder than they ever did to get into pubs and it's creating a vodka drinking culture on the beach and in the town square."

Mr Martin's comments come after Northumbria Chief Constable Michael Craik called for under-21s to be banned from drinking in public because his officers were becoming "overwhelmed" by drink-fuelled rapes and assaults.

Mr Craik said: "Every act of violence, every violent offence, every rape we come across is increasingly caused by drinking.

"It is a serious problem that we have tolerated for too long. Something has to change."