A cancer charity has welcomed the government's move to increase the legal age for buying tobacco products from 16 to 18.
The new law has come into effect in a bid to improve smoking cessation trends among young people.
It follows the ban on smoking in enclosed places in England which came into force on July 1.
Health minister Dawn Primarolo said: "We are determined to reduce the number of young people who smoke.
"Raising the legal age of sale to 18 will make it easier for retailers to spot underage smokers and lead to less young people becoming addicted to nicotine and continuing to smoke into adulthood."
Jean King, Cancer Research UK's director of tobacco control, added: "It sends out a strong message that tobacco products are dangerous, but strict enforcement of the law is crucial for it to have the desired effect.
"Smoking is a serious problem among young people - 16% of boys and 24% of girls aged 15 are regular smokers - so youth smoking must remain a Government priority if we are to prevent these teenagers from becoming adult smokers and greatly increasing their risk of developing cancer in later life."
"I think it is a law that has not been thought out and is symptomatic of credulity. Some of the kids at my school were far younger than 16 when they started smoking (one I recall was only 8!). If you asked them why, they said it was because it made them feel like adults. Raising the age to 18 is likely to make things even worse and for those 16 and 17 year olds, then there is nothing like the forbidden fruit. Given the Government's woeful record on illegal drug control, this new law must seem like manna from heaven for the drug pushers that are responsible for so many of society's problems. They have been given the opportunity to expand their portfolio into providing legal drugs." - Name and address supplied