Nelson's garden

The answer lay in a new tourism campaign to promote the city's "villages" - from urban Marylebone to suburban Wimbledon and from Primrose Hill to Blackheath. Visit London-decided the best way forward would be to lay 2,000 square metres of turf all round Nelson's Column. The grass arrived overnight and by dawn Trafalgar Square had gone green.

The grass will remain in place for only two days before being taken up and transplanted elsewhere in London. The bizarre sight of one of the world's best known landmarks laid to turf is sure to attract thousands over the coming 48 hours.

The metamorphosis left Nelson with a new green backdrop that spanned the area between the two fountains while the much-maligned pigeons seemed put off by the new surface and gathered on the sidelines.

The 40 tonnes of turf were laid in metre-wide strips 20 metres long and watered with a fire hose. The grass was transported from the Vale of York where it was dug up yesterday afternoon.

Visit London's Ken Kelling said today: "Hopefully people coming down specifically to see it and those who are just passing by will be able to enjoy it in the sunshine today. Once they have enjoyed something unusual like this they could go on to explore other green areas across the capital."

The turf will be transferred to Bishops Park in Fulham and planted beneath a row of plane trees close to the Thames.

Passers-by appeared bemused by the new view of the square. John Merry, 44, of Dartford, an IT manager for an investment bank, wanted the grass to stay for the whole summer.

Catering company worker, Agnes Stefanek, 35, of Pimlico, said: "I can't wait to grab some lunch and sit on it."