Last Friday, the morning after the local elections, I was returning to work late in the morning (having got home towards 5am). I’d foolishly forgotten my iPod, so I could hear the voices of the commuters I passed on the Jubilee Line platform. One was very nasal and very familiar. I turned and saw Ken Livingstone waiting for the next train, newspaper in hand.

So I went and said hello. He seemed fairly dispirited and not optimistic about the mayoral election result. Turns out he was right.

In the week since taking office, Boris Johnson has launched one deliberately eye-catching initiative: to ban alcohol on London’s public transport network. So much for selling yourself as a liberal when your first act is to ban something. I wonder why he didn’t make more of this plan during the election – did he make it up in two seconds after getting elected, or was he afraid some of the more, let’s say, light-hearted of his supporters might have been put off?

Anyhoo, the ban takes effect on June 1st. Quite aside from whether it’s liberal or not, will it make a difference? Drunks are probably the least likely to take notice of it. The law-abiding majority who had the odd drink on the Tube will stop, and be slightly less free and enjoy their evenings slightly less.

And who does drinking on public transport actually harm, as long as it’s not the driver doing it? Drunkenness can be a problem, but Boris hasn’t banned drunk people from public transport (as Chris points out, the night bus network would be unsustainable if you did). He isn’t introducing more staff to enforce the ban and he isn’t clamping down on anti-social behaviour generally. The ban might succeed in reducing litter on public transport very slightly but that’s about it.

So a policy that grabs headlines but costs virtually nothing to implement (the politician’s favourite), that inconveniences some people while not noticeably increasing quality of life for anyone else, that misses the real target, but which, in true New Labour style, Sends A Message. Unfortunately, that message is that if you reach your tube station with a half drunk can of beer (or M&S G+T if that’s your preference), you should down the rest before trying to catch a train.