Pubs, hotels, restaurants, clubs and offices in Scotland became smoke free yesterday as the first ban on smoking in enclosed public places in the UK came into effect.

After 6am yesterday, it became an offence to light up in any enclosed public space. Anyone flouting the ban faces an on-the-spot £50 fine from the army of enforcers hired by local councils to ensure the ban is upheld. Any business that does not put up No Smoking signs faces a £250 fine. Despite this, around one-fifth of smokers told a BBC poll they planned to ignore the ban.

However, Scotland's first minister, Jack McConnell, insisted the vast majority of Scots would respect the ban. Speaking on BBC 1's Sunday AM, he said: "I think we've got to be realistic about this. There are going to be people who will be inconvenienced by the ban. But I also believe Scotland is a law-abiding country. People will want to make this ban work in practice."

As pubs and restaurants across the country held "last suppers" for smokers, lobby group Forest claimed smokers were being victimised by Scottish politicians.

Neil Rafferty, spokesman for Forest, said: "Scotland is less free than it was last week. Politicians now have a licence to intrude into our private lives and there is no doubt they will continue to use it. Those non-smokers who cheered for the smoking ban should know they are simply appeasing extremists."

Around 30% of Scots smoke, the highest figure in the UK, and the country has one of the worst health records in Europe. Tobacco kills around 13,000 Scots every year and it is estimated that up to 2,000 people die of passive smoking annually. A record number of Scots are thought to have quit smoking yesterday.

Neil Douglas, president of the Royal College of Physicians of Edinburgh, said: "For those who smoke, there has never been a better time to stop smoking. For those who cannot quit, now is a time to think how to limit the harm you do to others by smoking and particularly how you can avoid smoking near children."

As rain poured across much of Scotland yesterday, unrepentant smokers could be seen huddling in newly built shelters. "I think it's shoddy. There should be smoking places and non-smoking places," said Leo Federici, a nightclub promoter smoking a cigarette outside an Edinburgh bar.

Although only a quarter of smokers back the ban, surveys suggest that around 60% of Scots are in favour of it. Scottish publicans claim the ban will cause up to 140 pubs to close and will cost 2,500 jobs.

But in a pub on Edinburgh's Grassmarket, waitress Kathy Eager was impressed. "I'm loving it. Normally I'd have to go home and scrub the smoke out of my skin," she said.

Not everyone, however, was so thrilled. Artist David Hockney told Sunday AM: "This is a very, very mean-spirited act by people who I think don't know what they're doing. Pubs aren't health clubs. I've smoked for 50 years and now I'm told I can't be social anywhere at all. I'm fed up with the prigs."

England, Wales and Northern Ireland will impose smoking bans next year.