(CNN) -- A British mother has been given a suspended sentence after her toddler was filmed smoking a cigarette in front of her.
Kelly Marie Pocock, 24, pleaded guilty to one count of cruelty to a child under 16 at a hearing last month, the British Press Association (PA) reported.
Details of the case emerged when she appeared in the Merthyr Crown Court on Thursday for sentencing and were reported by PA.
Prosecutor Jonathan Rees told the court: "The video demonstrates the boy placing a cigarette into his mouth, lighting it with a lighter and sucking, drawing smoke clearly into the lungs and he seems to do it with some accomplishment.
"It doesn't cause him any discomfort. He is sat on a chair close to the mother, who is talking on the phone.
"It is clear that the boy, at the age of three, knows what to do with a lighter and cigarette," Rees said.
PA reported the court was told the three year old was filmed on a mobile phone by Natasha Dudley, a friend of the boy's mother.
The prosecutor said Miss Dudley had gone looking for the boy while visiting Pocock's home just after Christmas 2007.
"She found him underneath the bed with some cigarettes," Mr Rees told the court, according to PA. "He was actually smoking one at the time and Miss Dudley said it looked like he had been smoking for many years."
After the boy was taken downstairs, the court was told he went into the living room, picked up a cigarette butt from an ashtray and smoked it. His mother was nearby talking on the phone.
It was at that point that Miss Dudley filmed the boy on the phone and later forwarded it to social services.
Pocock is reported to have pleaded guilty on the basis that she hadn't seen her son smoking on that occasion, or ever before, PA reported.
In an interview with police, she is said to have told officers that she was "shocked" when the matter was drawn to her attention.
Judge John Curran told the court the case was one of the most "extraordinary" he had ever come across, PA reported.
He said the boy would not have been able to smoke without discomfort "unless he had acquired a habit."
"This is an appalling situation and I don't see how, despite your basis of plea, you could have been unaware of the fact."
Judge Curran sentenced Pocock to 40 weeks imprisonment, suspended for two years. He also imposed a 12 month supervision requirement as part of the sentence, PA reported.
Judge Curran added that while the offence would normally attract a jail sentence, he didn't want to cause her children any further emotional harm by separating them from their mother.