160-year-old dream takes shape in Trafalgar Stair

The dreams that architects have entertained for Trafalgar Square for 160 years are at last taking shape with the first big changes to the square since it was built as a symbol of the might of the British Empire.

Workers this week began to build a grand staircase as part of a £20m project designed to transform the grimy, traffic-besieged square into a Continental-style piazza.

The steps, which will lead across a pedestrianised terrace to the National Gallery, have featured regularly in designers' plans since Parliament approved the square in 1826 – but they have always been rejected.

However, in a new attempt to shift the transport balance in central London away from the car in favour of pedestrians, the project is now on schedule to be finished by May.

Plans for a staircase were first suggested by William Wilkins, who designed the National Gallery in 1831, in a competition to create Trafalgar Square to celebrate the power of Britain's naval fleet and the heroics of Lord Nelson.

A staircase was included in the original design of William Railton, the man behind Nelson's Column, but only as a way to raise his grand design even higher.

Sir Charles Barry, the architect eventually responsible for the layout of Trafalgar Square, which was completed in 1845, also considered a giant staircase. Sir Charles opposed the installation of Nelson's Column and would have included stairs if the monument to the hero of Trafalgar had been smaller.

Further variations on the theme were proposed, including one in 1894 by William Woodford, which was the closest to the current plan.

Work began this week to dismantle the northern wall of the square to make way for the staircase. Some of the original stone, large blocks of DeLank granite, will be taken back to the Cornish quarry where it was mined to be recut and used in the new scheme. A lavatory, café and lifts for the disabled will be incorporated into the new design,l and heritage wardens will be employed to keep the area clean. The last of the pigeon-feed sellers have now gone from the square.

Peter Heath, the design team co-ordinator, said: "London hasn't really had Continental-style squares with big staircases like many European cities. That in itself makes it interesting. It's a bit of a tweak to get the balance between pedestrian and vehicle use."

The design will allow pedestrians to criss-cross the square. Wider pavements are also being built in nearby streets to make it a more pedestrian-friendly area.

Congestion-charging, soon to be introduced, will probably also cut car use.