It follows reports that proposals to reduce traffic in Trafalgar Square and Parliament Square - due to be voted on by Westminster City councillors next Tuesday - have been rejected by Government focus groups.
The plans were to close some of the roads alongside the squares to enable visitors to stroll more freely outside Westminster Abbey and the Houses of Parliament, and in front of from the National Gallery.
Similar schemes operate in Leicester Square, Covent Garden and in front of Buckingham Palace.
A ministerial meeting chaired by John Prescott, the Deputy Prime Minister, was held in March to decide how the Whitehall project should be taken forward.
Now the masterplan will be discussed by Westminster council's planning committee.
Mr Prescott has given the proposal his blessing. He said: "I am delighted that we have a masterplan that shows how the historic heart of London can be returned to the people.
"I am looking forward with great interest to taking delivery of the final proposals."
But Paul DeZylva of Friends of the Earth fears focus groups have rejected banning cars because it would be unpopular with the middle classes.
He said: "Pedestrianisation is an important feature for central London and we would be supportive, although it is not a total solution. It sounds as though Tony Blair is keen to bend over backwards to appease polluting motorists.
"If we cannot get pedestrianisation in central London, then we don't stand any chance of pedestrianisation elsewhere."Reuse content