Work to create a grand central staircase in Trafalgar Square is starting nearly 160 years after the square was completed.

Dismantling of the north wall will begin on Thursday, to make way for a staircase linking the square with the pavement in front of the National Gallery.

A central staircase was first envisaged by William Wilkins, who designed the National Gallery in 1831.

Plans for a staircase were shown in William Railton's original design for the Nelson memorial and were also pursued by Charles Barry, the architect responsible for the fountains and lay-out of the square.

Reduce cars

The Greater London Authority believes the popular tourist attraction is being choked by traffic and needs to be more pedestrian-friendly.

It plans to reduce cars circling the square and create a new public space that will become a centre for concerts, street entertainment and other events.

The stones from the dismantled wall will be used for the staircase.