One of the first things Boris Johnson did in May, as the new mayor of London, was to ban the drinking of alcohol on public transport, particularly on the Underground. Previously this had not been an issue much raised by Londoners in my experience, but the ban – and along with it the authority of the mayor – may well come up against its biggest challenge on New Year’s Eve when free travel will be offered on the tubes and buses of London for all the revellers.

It’s a time of year which attracts and encourages a lot of drinking including in public and often on our transport system. So how is Boris going to enforce his ban? Extra police cells could be appropriate, as I suggested in jest at the last Mayor’s Question Time on the 17th of December. Maybe we have time enough for an one-evening amnesty to be put in place. Now this could be a real test of Boris’s mettle and his libertarian credentials, both at the same time!