Part of the new law requires all enclosed workspaces to have at least A5-sized no smoking signs on the premises or be fined up to £200. The FSB is concerned that, although the smoking ban has been well-publicised, not all firms will know that they have to display signs. The fines for lighting up in a workplace for individuals (£50) are also much lower than for businesses where someone is caught smoking (up to £2,500).

The FSB is calling for a proportionate response from the authorities with a verbal warning, followed on the second occasion by a written warning before a fine is levied on the third instance of a breach in the new law. This would allow businesses to adapt to the new rules with guidance from the authorities rather than them being hit with a fine straight away.

Mary Boughton, FSB Health and Safety Chairman, said, "The enforcement agencies have to apply common sense to this ban. It is not good enough for them to go straight into businesses and hand out on-the-spot fines for a lack of no smoking signs.

"We need to see a 'three strikes and you're out' policy where enforcement agencies provide advice for businesses on how to meet their obligations before fines are handed down. If this does not happen then it will only breed resentment and resistance to the smoking ban and neither we nor the Government would want this to happen.

"We would urge all businesses to go to the smoke free England website to get their free signs. This will protect them from fines and will also ensure that, if someone ignores them and smokes on their premises, they will have a defence against further action."

The Government has meanwhile issued instructions to local authorities to take a softly softly approach in the early stages of the ban to give people time to adjust to the new regime.