Katy Guest: What, no quick snifter on the Circle Line?

Saturday, 9pm, Liverpool Street station, the penultimate carriage on the Circle Line – this will be the venue for my kind of political protest. Between 10.30 and 10.45pm a small bunch of outlaws will drink a toast to former Mayor Ken. From Sunday onwards, they may never legally drink on the Tube again.

As hard as he tries to explain it, Boris Johnson cannot convince me that taking a drop on public transport is such an obnoxious crime. He says that he wants to stop violence on the Tube. But I thought that violence was banned already. He's against chucking up in public. Well I've been on the 11.45pm Vomit Comet many times, and I've never seen anyone drinking while they're on it – they're way too far gone for that. He thinks that nobody likes seeing "people swigging from bottles". There's a lot of things that people don't like to see on the tube – swigging and bottles are the least of them.

The ban is even harder to understand given Boris's libertarian views about smoking in public places. "It is extremely difficult, statistically, to contract a cancer from passive smoking," he said when that ban was introduced. Passive drinking, on the other hand, leaves many innocent bystanders riddled with cancer. For years he has been campaigning against this "persecution of smokers" and the erosion of civil liberties it represents. Perhaps if the Licensed Vintners Association were to pay him thousands of pounds, as the Tobacco Association did, he might see things differently.

Opposing the alcohol ban, Bob Crow of the RMT focused on the problem of enforcing it. "Perhaps the Mayor will come out with his underpants over his trousers like Superman one Saturday to show us how it should be done," he said, "and maybe tell a crowd of Liverpool supporters that they can't drink on the train." Poor Liverpool supporters, who I happen to know are civilised individuals who can take their ale and respond well to reason. I see Mr Crow's point. But if staff can't stop sober people behaving like scumbags on buses (and they can't), it might be easier to stop drunks, who are handicapped by falling over, falling asleep and singing little songs about pixies.

Boris, with a novice's optimism, thinks that "people will find it self-enforcing like the smoking ban after the King's Cross fire."

Let's leave aside the utter crassness of comparing a sneaky G&T on the bus into town to a horrific ordeal that left 31 people dead – it's Boris Johnson, after all. Londoners don't protest anything on public transport any more, whether through fear, British reserve or plain old resignation. So they're not going to speak up against someone who is cracking open his 15th Stella and beating up the granny next to him. And if the drinker is not being anti-social or aggressive, why would anyone want to stop them?

Even more pathetic than this, though, is the Government's plan to copy everything Boris does in its desperation to stay elected – now they plan to roll out prohibition across intercity transport, too. I've seen a romance start over a shared bottle of Midland Mainline wine, a carriage collapse in laughter thanks to a woman and her cider in Bristol Parkway, and a party get going on a train to Edinburgh when the air-con broke down and drinks were free.

This is why I'll be on the Circle line this weekend, toasting Ken, who understood that a wee dram does not always lead to the collapse of civil society. And why from now on you'll see me on the 171 of a Saturday night, sipping quietly from a Coke can that may not necessarily contain Coke.

If Cohen's a hack, I'm a poet

Leonard Cohen proved to be far less irascible than I expected, and much sillier, when I heard him interviewed earlier this week on Radio 4's Front Row. Highlights included Mark Lawson asking the great man whether he notes down sights like, say, the sun shining down like honey on Our Lady of the Harbour, in a little spiral bound notebook, and Cohen replying that yes, "much of my work I consider journalism". (Much of my work I consider to be growly-voiced folk poetry that makes grown men cry, so I'm glad he mentioned that.) It was a scoop, also, when the great lyricist admitted that he uses a rhyming dictionary to write his songs. Though not for Hallelujah: knew you/ fool you/ outdrew you/ Hallelujah could only have come from his head.

* When I was a teenager in Plymouth, a certain sort of girl used to hang around the Barbican, hoping to be taken as a muse by the local artist.

The artist we were after was Robert Lenkiewicz, an enigmatic handsome bastard and the subject the sort of rumours particularly beguiling to middle-class girls who aimed to go to the bad. I never made it into Lenkiewicz's studio (which is probably for the best). I should have headed to the Hoe, where I'd have had a much better chance with the other famous local artist, Beryl Cook.

I remember The Dolphin pub, where Cook's crazy ladies and fat-bottomed girls used to hang out, and the queue at Cap'*Jaspers, which was the image of one of her paintings.

Such is life: you think you're a brooding Anna in a Blue Dress, and then you realise you're happy to be Dancing the Black Bottom. It's one of the funny things about growing up.