Chief medical officer Liam Donaldson has revealed that he considered quitting after the government failed to heed his advice on a total smoking ban.
During a health select committee hearing on smoking today, Mr Donaldson said he decided to stay in his job to fight for a complete ban.
He said a partial ban would be an "unworkable situation", but did predict that a full ban would eventually arrive.
"My feeling is that this will eventually come and it's more likely to come if I stay in my post and continue to champion it, " he told a panel of MPs.
Mr Donaldson also said a partial ban would be worse for health inequality than no ban.
And with the new licensing laws and an increase in opening hours, he added that bar staff would be exposed to second-hand smoke for longer.
Earlier the government's plans to ban smoking in public by 2007, with exemptions for pubs that don't serve food and private members' clubs, came under more fire.
Graham Jukes, chief executive of the Chartered Institute of Environmental Health said: "Enforcing exemptions would be a complete and utter waste of public funds and resources."
Cllr David Rodgers of the Local Government Association told MPs: "We believe the bill would increase health inequalities and flies in the face of the idea that it would improve public health."
Deborah Arnott, director of Action on Smoking and Health (ASH), said she believed that public opinion was moving in favour of a complete ban.
She pointed to research from 2003 which showed 20 per cent of the public wanted smoke free pubs, whereas now this figure is 41 per cent.
Meanwhile in Ireland, where legislation was introduced in March 2004, Ms Arnott claimed support for the ban continued to grow after it was first brought in.
In the final session health minister Caroline Flint defended the government's position.
She stressed that the proposals still gave people choice and added: "Part of what we are trying to do is have a light-touch of enforcement."