On the other hand, smokers are like lepers, cast to the doorways and frowned upon by their peers. And it seems their misery could worsen, with the habit even costing them their careers.

In December, the World Health Organisation (WHO) introduced a policy of non-recruitment of smokers.

The WHO has decided not to employ people who smoke any tobacco product daily or even occasionally. The organisation says it is because 'tobacco is the major preventable cause of death in the world, killing nearly five million people annually'.

The WHO says that, because it is at the forefront of the global campaign to curb the tobacco epidemic, it has a responsibility to ensure that this is reflected in its work, including its recruitment practices and the image projected by the organisation and its staff. It has not banned staff from smoking, but it has been encouraging them to stop by introducing various measures.

The WHO is not alone in its move to relegate smokers to the bottom of the employment pool. Companies throughout Europe and the US have been implementing non-recruitment of smokers policies over the past few years. Last year, a German company sacked one of its employees for smoking at home. The company, which runs a health and fitness programme for its staff, had hired a detective to catch the employee in the act.

It was also reported earlier this year that Marks & Spencer has banned staff from smoking in public while wearing their company uniform. But where will we draw the line and what control do employers have over their staff?

"Employers are doing drug tests, background tests and health checks, so it isn't surprising that some are beginning to do this, " says Matt Doyle, senior consultant with accounting and financial services recruitment specialists, SSC Recruitment.

"If the profile of a smoker doesn't fit in with their policy, it is the employer's prerogative not to hire them. But it may be costing the company good potential employees."

However, Doyle says he cannot see non-recruitment policies towards smokers taking off. "The health services sector may do it, but in other sectors it's going to reduce the number of people who can get the job. I can appreciate why employers are diligent about checks in recruitment, but once you get in the door I would draw the line."

The non-recruitment of smokers does not fall under the remit of the Equality Authority. The authority deals with discrimination on nine grounds: gender, marital status, family status, age, disability, race, sexual orientation, religious beliefs and membership of the Travelling Community.

Nevertheless, Richard Grogan, partner with PC Moore & Co Solicitors, says employers in Ireland who take on such non-recruitment policies may "face a plethora of proceedings and will need to gear themselves up for the serious litigation that will invariably follow.

"I would have a serious concern if we got into a scenario in Ireland where employers are setting criteria for jobs that are not job specific, " he says. "An employer is certainly entitled to set conditions relating to employment, but saying that, the condition would have to be reasonable. In my view, the issue to be considered should be whether the person is capable of doing the job."

The ban on recruitment of smokers is legal under international law, which governs operations at the WHO and other UN agencies. If smoking on one's own time becomes a sackable offence here, job seekers and employees could appeal decisions under the European Convention on Human Rights Act, 2003 (ECHR).

Article 8 of the ECHR says that everyone has the right to respect for his or her private and family life, home and correspondence. Restrictions on this are only justified if there is a threat to national security, public safety, the protection of the health or morals of others, the prevention of disorder or crime or the protection of the rights of others.

"I certainly think there would be considerable issues in relation to the invasion of a person's privacy, " says Grogan. "In addition, I would have a concern that if we had a situation where employers in Ireland could decide not to hire a smoker, then they could also decide not to employ individuals for many reasons. It would leave the door open for someone not to hire because a person drank or held membership of a particular sporting group."