Leading article: A powerful and positive image

Those perplexed by the notion of a disabled person on a pedestal might bear in mind that Nelson, whose own monument adorns the same square, had one arm. The sculpture is also a clever echo of those revered icons of antiquity such as the Venus de Milo and the Apollo Belvedere, neither of which is considered ugly because of its missing limbs. The sculpture provokes thoughts on heroism too. According to the Mayor of London, Ken Livingstone, whose office underwrote the project: "This square celebrates the courage of men in battle. Alison's life is a struggle to overcome much greater difficulties than many of the men we celebrate and commemorate here."

Not all will agree with this. But the virtue of the sculpture is that it encourages people to address such issues. Some have taken issue with Quinn's workmanship, calling Alison Lapper Pregnant a "concept" rather than a sculpture. But this is a side issue. It is true that Quinn's work was created with moulds. But so were the bronzes of Henry Moore, which adorn many a public space. And we must be careful not to be drawn into a sterile debate about the merits of conceptual art.

Regardless of whether people like this artwork aesthetically or not, it has generated a welcome debate about public sculpture and what it is for. From Antony Gormley's iron figures in Liverpool to Millennium Square in Bristol, public art in Britain is capturing the imagination. Giancarlo Neri's sculpture of a giant chair and table on Hampstead Heath has become a focal point for the local community in a way that few anticipated.

Controversy was recently generated over a rock sculpture called Monolith and Shadow commissioned to stand outside a new London hospital. It was described as a "£70,000 pebble" by the down-market press. But this only served to demonstrate their knowledge of the price of everything and the value of nothing. Public art, whether commissioned by the public or private sector, has the capacity to enhance our cities and our quality of life. Alison Lapper Pregnant is a welcome addition to our capital's collection of artistic riches.