The average age to start smoking in Britain's most deprived town is just nine, according to a National Health Service survey cited Thursday by The Sun.
But many are even younger. One boy got hooked aged three because his grandparents thought it was funny to give him cigarettes.
The shock findings came from Merthyr Tydfil, in South Wales -- blighted by few jobs, poor wages and dependence on state benefits.
"Unfortunately, it is realistic. I had a patient who started between two and three. His parents gave him cigarettes because they thought it was funny," researcher Tracey Bowen said.
The study was carried out after medics noticed the high number of tobacco-related illnesses in the former industrial town.
"These figures are truly alarming. Childhood smoking is quite rare -- less than one percent of people under 11 smoke regularly -- so this is unusual," said smoking expert and Birmingham University professor Paul Aveyard. "It is worrying, as you become more addicted to smoking the earlier you start. Starting younger is also associated with a higher risk of smoking-related diseases."
Merthyr, population 55,000, has one of the UK's lowest life-expectancy rates and one of the highest rates of people claiming health-related state benefits.