A pub which twice sold alcohol to youngsters under 18 has become the first in West Sussex to be prosecuted and fined under new laws.

Police were disappointed with the £250 fines imposed when the maximum could have been £5,000.

But the pub backed the police.

A spokesman for the Lamb Inn in Steyne Street, Bognor, said: "We support the police but it is so difficult sometimes telling someone's age."

The Lamb was the subject of two test purchases by police and Trading Standards in October.

On the first occasion, volunteers aged 15 and 16 ordered and were served alcohol by the licensee, Vanessa Morris.

The pub was warned but two weeks later two more teenage volunteers went into the pub and were served by a member of the staff who later received an £80 fixed penalty notice.

At Chichester Magistrates Court on Tuesday, Mrs Morris was fined £100 for the first offence, £150 for the second offence and ordered to pay £55 costs.

Stephen Lawson, supervisor at the Lamb, said: "We are behind the police crackdown on under-age drinking and we have always supported the police.

"We have notices up in the pub but it is very difficult sometimes for us to tell someone's age.

"We are now asking more and more customers for proof. One customer we checked recently turned out to be 30."

Chief Inspector Brian Bracher, Arun district commander, said: "The message is clear - if you sell to those who are under age, you will be prosecuted.

"The conviction is only the first part of a process. We will now be attending a hearing to review the pub's licence.

"The use of test purchasing operations will continue in the Arun area.

"We want this to be a reminder to licensees that they will not just be cautioned for offences but prosecuted and put before the courts.

"I have noticed that more and more licensees are asking for identification if a person appears to be under age.

"All licensees need to be sure that their staff have the confidence to challenge people about their age and, when necessary, refuse to serve them."

Chief Superintendent Mark Streater, divisional police commander, said: "This was the first prosecution of its kind in West Sussex under the Chief Constable's (Ken Jones's) Enough is Enough campaign banner which aims to tackle yobbish behaviour fuelled by alcohol.

"The sentence on this occasion was disappointing as fines of up to £5,000 could have been imposed by magistrates, which highlights just how seriously these offences should be taken.

"However, we are pleased to have achieved a successful prosecution and the hard work will continue across West Downs division to tackle under-age drinking head-on.

"The manner in which alcohol is purchased and consumed must become an institutionalised responsibility within the licensing trade in West Sussex.

"If not, our communities will continue to suffer the physical and financial costs of drink-fuelled yobbery and violence.

"Sussex Police will not stop pursuing any pub, club or shop that continues to flout the law.

"I look to the magistrates courts to give us maximum support in dealing robustly with serial offenders."

Jean Irving, West Sussex's violent crime reduction manager, said: "Under-age drinking will not be tolerated across West Sussex as this has a direct impact on increasing public place violent crime.

"We will continue to put resources in to this long-term initiative and these type of operations will be conducted regularly across the whole of the county."