Pubs and bars found guilty of persistently selling to minors face a three month close or £10,000 fine under a Home Office Spring crackdown.
The offence of Persistently Selling Alcohol to Minors goes live on Good Friday (tomorrow).
The police will be able to use the new powers as part of a national "tackling underage sales of alcohol" campaign, which begins on 4 May in England and Wales.
If a pub, bar or off-licence is found guilty of selling to minors on three separate occasions during the 10-week length of the campaign they face a £10,000 fine or three months closure.
Every police crime reduction unit is being instructed to target at least 20 premises within their remit with repeat test visits.
David Hollis, associate at solicitors John Gaunt, said: "The conviction, caution or payment of fixed penalty do not need to relate to the Premises Licence holder."
"This means that sales by staff members will count, even if the Premises Licence holder would have a due diligence defence on each individual sale. Therefore, one immediate step you need to take is to ensure that you are notified by all employees of any underage sale at the premises, especially those that have led to a fixed penalty notice, caution or conviction."
By Christopher Walton
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