The first stages of a law effectively banning spontaneous protests near Parliament have come into force.
Mr Haw could be the first to fall foul of the new law
People who want to demonstrate inside a new half-mile exclusion zone can apply for police permission from Friday.
From 1 August, unauthorised protesters within the zone could be removed or arrested. Critics say the zone is too big and is a "contempt of democracy".
The Home Office says it puts protests on the same footing as processions, for which police also need to be notified.
The Serious and Organised Crime and Police Act, parts of which come into force on Friday, grants the home secretary the power to ban unauthorised protests within a half-mile radius of Parliament.
Within the zone, police have powers to set time limits on protests and ban loudspeakers and placards.
It was aimed at removing lone anti-war protester Brian Haw, from Worcestershire, who has been in Parliament Square for four years, despite attempts to evict him.
Some MPs said his numerous placards were an eyesore and his attacks on government policy - often made through a loudspeaker - were distracting them from their work.
The government says there must be a balance between the right to protest and the rights of the people working in Westminster.
But its critics say there is no need to extend the ban over such a wide area - it will cover St James's Park, much of the South Bank and Charing Cross to Lambeth Bridge.
There were clashes at last year's pro-hunt protest in Parliament Square
The London Eye, scene of an 18-hour Fathers 4 Justice protest last September, is also included in the zone, although traditional protest venue Trafalgar Square is not.
Shadow Home Secretary David Davis described it as a "contempt of democracy and a contempt of people's right to protest."
But a Home Office spokeswoman told BBC News: "It isn't going to ban protests at all - it's putting them on the same sort of standing as processions. If you are processing through London you have to let the Met know.
"What this will do is put static protests on the same footing."
She said the designated area would cover a number of government buildings, including Downing Street, MI5 and the Ministry of Defence and had been decided on in consultation with the Met.
The London Eye is covered because it was considered a large scale protest could still obstruct access to Parliament because of its position over Westminster Bridge, she said.
She said unauthorised protesters could be arrested, but that would be a matter for the police to decide.
Mr Haw said he was awaiting legal advice on the new ban.