Flanagan, mindful of his responsibility to uphold the law since his 2011 election to the Dáil, has said he will not smoke or consume cannabis on Irish soil. He only partakes when in countries that allow the practice.

His attempt to legalise cannabis in Ireland is doomed; when the two-day debate is finished, the majority of politicians in Dáil Eireann will rush to vote ‘no’, to burnish their anti-drugs credentials. They are likely to head to the Dáil bar to swig alcohol to celebrate on behalf of responsible Ireland.

Our use of alcohol emphasises that legalisation confers legitimacy, which promotes use, and then misuse. If drugs are legalised, then the supply is increased and that, in turn, increases use and misuse.

However, alcohol consumption was regulated because of the poitin culture and that is why drinking in public houses, rather than in homes, was encouraged in the late 19th and early 20th centuries.

People will drink, so intake must be controlled at relatively healthy levels; the same applies to cannabis use, whether it is legal or not, good for the health of people or not.

Even if Flanagan has no chance of winning — few politicians want to be perceived as ‘soft’ on drugs — he is right to provoke debate, because an enormous amount of the argument against the legislation of cannabis is self-righteous, ill-informed, unscientific waffle.

Where he may be wrong is in portraying cannabis as not merely harmless, but as good for people.

I’d draw the line at that. I prefer to allow adults decide what they do — as long as they, and not the rest of us, pay for any consequences, such as higher medical bills — but it would be wrong to dismiss potential side-effects of cannabis.

Cannabis is mood-changing; if it wasn’t, its users would not consume it. There is evidence it can be mind-altering. Many doctors, psychiatrists and psychologists believe that, in young people, psychosis was brought on by the use of cannabis.

Again, caveats abound.

Some young people might have developed psychotic illnesses anyway, with or without use of the drug, but there are grounds for believing that cannabis use was a contributory factor. But such a predisposition could be triggered by another drug, such as alcohol.

The numbers who succumb to paranoid schizophrenia, apathy, and chronic addiction seem relatively low, especially compared to other drugs, both legal and illegal. However, it would be remiss not to concede that some users become psychologically reliant on cannabis.

One of the problems with illegal drugs is that nobody knows what they are buying. For a few years, health specialists have been warning that the marijuana being sold in Ireland is of a much greater potency than was available to previous generations. It is often grown in industrial-style conditions in Ireland, a genetically modified crop that is more addictive and potentially damaging to the health of the user.

Only a few weeks ago, this newspaper reported a case from Dublin Coroner’s Court, where consultant stroke physician, Joseph Harbison, told how doctors at St James’s Hospital had seen “five or six cases” of young people having strokes, following the use of herbal cannabis, in the past three years.

Dr Harbison said the heavy use of high-potency cannabis is putting young people at risk of stroke.

“The cannabis available in and around Ireland, at the moment, is typically hydroponically grown [grown in water] and has a very high potency,” he said. “I now strongly suspect that we are seeing the consequences of younger people developing an arteriopathy [arterial disease] related to the direct irritant effects of this new, potent cannabis.”

The coroner recommended medical and scientific studies, but the consultant said his warnings were based on heavy use of cannabis and not just the occasional joint. Still, it is worrying.

But, perversely, this provides a strong argument for the legislation of the packaging and sale of cannabis/marijuana.

If these illegal drugs were prepared and packaged under licence, the potential for regulating the potency and quantity of the doses would be greatly improved.

There are other benefits to legislation. Putting the business in the hands of licensed operators may combat the drug gangs who use extreme violence as part of their underground, illegal businesses.

It won’t put them out of business, but it will put them to the margins, as it has with illegal alcohol and cigarette distribution.

Then, the gardaí could concentrate on intercepting the supply of more dangerous drugs, such as heroin, cocaine and their derivatives.

The gardaí could return to the good idea they had in 2006 and which they applied briefly, until Justice Minister Michael McDowell expressed his displeasure — to merely caution users of cannabis, rather than wasting time seeking prosecutions for possession.

A legitimate industry can be taxed, providing income to the State to pay for health treatments required because of misuse of drugs. Price can moderate consumption, as it does with cigarettes and alcohol. Lower consumption can be less of a drain on State resources. I don’t know if Israel’s experience can be applied to Ireland, but Flanagan’s contention that his measures would improve our finances by €300m annually — between taxes and money saved — is interesting.

HIS bill aims to decriminalise the possession, cultivation and sale of cannabis. He wants to make it an offence for a person to sell the drug without a valid wholesale or retail licence. Those licences could be granted to wholesalers, shops, pharmacies, coffee shops and ‘cannabis social clubs’. The latter would be obtained through a district-court hearing and would allow the holder to set up, and grow, 300 cannabis plants, granting just six plants to 50 people apiece for their personal use. All cannabis products would be labelled with chemical and dietary information.

Flanagan said prohibition was “hugely costly, counter-productive and harmful”; he could have said, too, that it will never succeed, as it never has in any society. He might have exaggerated when he said legalisation would take all the power from dangerous dealers, and put it in the hands of the authorities. It would change the balance, but hardly to that extent. Legalisation would also change our attitudes towards drug addicts — we would see them as ill rather than as criminals. We treat people addicted to illegal drugs differently to people addicted to legal or accepted drugs.

We have a society that self-medicates with alcohol, and which has a developing tolerance for the excessive use of painkillers, sleeping pills, and anti-depressants. A greater number of people die in the US every year from prescription drug abuse than from the misuse of heroin and cocaine. We don’t ban them because they have benefits. We educate people to use them properly. Why not do the same with those drugs that are now illegal? Would it really make things any worse?

The Last Word, with Matt Cooper, is broadcast on 100-102 Today FM, Monday to Friday, 4.30pm to 7pm.