London Mayor Boris Johnson is facing calls to use his by-law powers to ban smoking in Trafalgar Square, Parliament Square and some parks.

Former health minister and cancer surgeon Lord Ara Darzi makes the recommendation in his report, called 'Better Health for London'. He says 1.2 million Londoners smoke, and 67 school children take up the habit every day.

The report also raising the worrying statistic that half of all adults in London are obese or overweight and the city now has more obese and overweight people than New York, Sydney, Sao Paolo, Madrid, Toronto and Paris.

Lord Darzi told the BBC: "London should lead the way for Britain, and the mayor should lead the way for London by acting to make our public spaces smoke free."

The report also suggests Oyster card discounts for commuters who walk part of the way to work, and suggests a ban on junk food shops near schools. Restaurants with more than 15 outlets should have traffic light warning labels on the menu, it recommends.

Would you support measures to ban smoking in public squares and parks, and prevent fast food outlets from opening near schools? Post a comment below.