According to the Trades Union Congress (TUC), the ban has worked because the law was backed by strong and simple regulation.
Commenting on the development, general secretary of the congress Brendan Barber said: "It was only when a legally enforceable ban was introduced across the whole of England that we saw exposure to second-hand smoke cut out at a stroke.
"Quite simply, the ban has made a world of difference to the health of millions of workers."
He added that the smoking ban was the one of the most significant occupational health measures the UK had seen for decades.
Meanwhile, a poll recently conducted by Monster revealed that 62 per cent of employees surveyed stated that the ban has had a positive impact of their places of work.
