Smoking is to be banned in all workplaces, including pubs and restaurants, in Northern Ireland from April 2007 it was announced this afternoon.
Gerry McElwee, head of cancer prevention at the Ulster Cancer Foundation in Belfast.
Northern Ireland Health Minister Shaun Woodward said the move would lead to the prevention of thousands of unnecessary deaths and smoking-related illnesses.
"This is an historic decision for Northern Ireland," he said. "This is not about banning smoking. People have that freedom of choice. What this decision is about is where people smoke."
His focus, he said, had been on the health of non-smokers and protecting them from the hazards of second-hand smoke.
Earlier this year Mr Woodward said he was considering at least partial smoking restrictions for the province but today he said that given "overwhelming health arguments" he had decided to opt for a comprehensive ban.
A survey by the health department showed 91 percent of people in the North, including smokers, favoured such a move.
Around 3,000 people die from smoking-related diseases each year in Northern Ireland, which has a population of 1.7 million.
The ruling was warmly welcomed by health organisations. "We're delighted. This is a big step forward for the health of people in Northern Ireland," said Gerry McElwee, head of cancer prevention at the Ulster Cancer Foundation in Belfast.
"No longer will employees have to endure cancer-causing substances in the line of duty. It will mean a significant improvement in the population's health and we look forward to working with employers, employees and unions to implement it."
Action on Smoking and Health (ASH) hailed the decision as "the most important advance for public health in Northern Ireland for 30 years", and said there was no excuse now for the avoidance of such a move in England.
Mr Woodward rejected claims the ban would damage Northern Ireland's hospitality industry, pointing to an increase in restaurant and bar business in New York in the year following the city's smoking ban in 2003, and a subsequent rise in job creation in the sector in both New York and the Republic.
However, pub owners, and drinks and tobacco firms, in the Republic have complained the ban has impacted hard on sales and has driven some publicans out of business.
Figures from the off-licence trade suggest people are opting to socialise more in their own homes since the ban.
Recent research has shown a sharp decrease in respiratory health problems among non-smoking bar staff since smoking was outlawed in the State's pubs and restaurants.
Another study showed that a year after its introduction, 93 per cent of people in Ireland believed the legislation was a good idea, including 80 percent of smokers.