Leading article: Performance art

We were never among Ken Livingstone's greatest fans. But one achievement cannot be denied him as mayor of London: the vitality of the street theatre and art that flourished in the capital under his auspices. Happily, this is one part of his legacy that Boris Johnson seems to be continuing with his characteristic panache. The fourth plinth in Trafalgar Square was a test case.

Having accepted a couple of weeks ago that "planning issues" made it impossible for him to use the plinth for a permanent statue of the Battle of Britain hero, Sir Keith Park – a promise he had made during his campaign – the new mayor undertook to keep the site as a showcase for contemporary works of art.

The latest winners, announced yesterday, follow in the tradition of the lively and often zany choices that have kept Londoners and their visitors talking since the show began. But none more so than Antony Gormley's project, The One and the Other, which will recruit volunteers to stand on top of the fourth plinth for an hour at a time.

What better way to reflect the infinite variety of all the to-ings and fro-ings at the very centre of the capital. For 100 days, the fourth plinth will become what anyone at any one moment makes of it: those who stand and those who watch will have something to contribute, as will those who merely watch the watchers as they pass by. And for anyone at a loose end in Trafalgar Square, there's a tantalising new photo-opportunity. If there's a queue to sit astride a lion, you can try ascending the fourth plinth and becoming a performance installation instead.