Campaigners have welcomed the announcement that Oxford Street will be pedestrianised by 2020.
The plans, announced to the London Assembly by deputy mayor for transport Val Shawcross, will transform the 1.2-mile shopping strip and tourist hub.
During his successful campaign to become mayor of London, Sadiq Khan committed to pedestrianising Oxford Street in an attempt to cut pollution and congestion.
Scientists named the road as the most polluted place in the world in 2014, based on monitors that measured nitrous oxide levels, a toxic pollutant linked with asthma and heart attacks.
Now the mayor has set out his plans to take vehicles off the iconic shopping street, which attracts more than 4 million visitors a week.
The changes will be split into two parts – starting with the western stretch of the road from Oxford Circus – and will coincide with the opening of two Crossrail stations on the road, expected to boost visitor numbers.
Living Streets, a charity that promotes walking, celebrated the “fantastic news”.
Joe Irvin, CEO of the charity, said: “We’ve long been campaigning for Oxford Street to be vehicle-free.
“Pollution and traffic are posing a threat to the public and undermining Oxford Street’s reputation as one of the world’s most iconic streets.”
“We urge him to move quickly. Early initiatives to have vehicle free days, reduce buses and taxis and limit speeds can begin almost immediately.
“This will ensure the Mayor can deliver on his ambition ‘to turn one of the world’s most polluted streets into one of the world’s finest public spaces.’
“We want Oxford Street to remain the thriving showcase shopping street of London and the UK.”