Dunnes Stores has been convicted of selling alcohol to a 15-year-old girl during a garda sting operation.
The conviction – the first in the supermarket's 65-year history – means shutting the doors on one town centre branch for four days and paying a €1,500 fine.
This is the first conviction under a new scheme which allows gardai to use children aged 15, 16 and 17 as undercover agents in off-licences and pubs which they suspect of selling alcohol to minors.
Drogheda District Court Judge Alan Mitchell said Dunnes Stores had not asked the teenager for proof of her age when she purchased four bottles of Smirnoff Ice from the chain's outlet on West Street, Drogheda, on December 9, 2011.
"The only question I was asked at the checkout was if I wanted a bag," the petite girl, who turns 17 later this month, said during her evidence.
Defending barrister Dorothy Collins claimed that the teenager looked older in the photographs taken before the 'test purchase of alcohol' operation.
This was disputed by Judge Mitchell who said he was satisfied that she didn't look older than her years even "today, over a year after the incident".
The secondary school student had been chosen from a group of students doing work experience in Drogheda garda station, Sergeant Donal McGivern said in evidence.
A number of other off-licences also served the same girl alcohol on the same night. But none of these establishments contested their cases and after donations to local charities, all were given the Probation Act.
This is believed to be the first conviction under a 2008 amendment to the Intoxicating Liquor Act.
Sgt McGivern said he stood behind her in the express checkout and watched while a cashier, who had a duty manager standing at her shoulder, served the girl the bottles of Smirnoff Ice.
She left the shop and handed the alcohol over to a female garda outside. The sergeant then identified himself to the cashier and the duty manager and cautioned them.
Judge Mitchell said Dunnes Stores had shown in testimony from a senior manager, Richard Ecock that it takes its responsibilities when selling alcohol "very seriously".