One rule for them ...

President Sarkozy's world class new jet is fitted with an 'air filter system, so that he can smoke cigars'.

Yes, France does have a ban, although enforcement does not seem thorough. It is a less draconian one than ours allowing employees of private companies to smoke in sealed rooms. But nonetheless it is a ban.

A writer in the Telegraph can explain to a UK audience that Sarkozy can smoke on the official plane because of the air filtration and expect them to make sense of the logic. Even though the logic doesn't apply here in the UK because officially there is no safe level of secondary smoke, the UK audience can follow it because it's common sense. Filtration (to take out particles that could be harmful) should enable smoking to take place without any damage to third parties.

But it's not legal, because the authorities declare it to be impossible that filtration can do the job.

The last high profile exemption to the smoking ban that I remember was at the G20 in London, 2009, when smoking was allowed at the Excel Exhibition Centre. There may be more, and each one undermines the fiction that smoke is not a negotiable, solvable problem. Because air filtration allows smoking: simple as.