A new"zero tolerance" campaign is being launched against graffiti.

The major clampdown has been ordered as a central element in a drive against anti-social behaviour in the capital and follows an inquiry by the London Assembly.

Not only will offenders be targeted with new vigour but, once traced and prosecuted, they will be forced to erase their work. Vandals will also face on-the-spot £50 fines.

Under the new Anti-Social Behaviour Act graffiti yobs, who cost Londoners £100 million, can be fined by community support officers, council officials and local authority security guards as well as by police.

If they fail to pay within 21 days, the fine increases to £75. If they still refuse, they face arrest and a possible prison sentence.

Retailers are also being targeted and those caught selling spray paint to vandals will face fines or prosecution.

Andrew Pelling, who led the Assembly's inquiry, said there was a new determination to clamp down on graffiti across the capital and disputed claims that the daubing is art.

" Many Londoners resent their environment being invaded," he said. "A distinction must be made. In some cases there may be some kind of message but a lot of it is just scrawling."

London boroughs spend £7million a year removing graffiti and London Underground has said it would need £10 million to replace all glass etched by vandals.