A protester who has kept an anti-war vigil outside Parliament for four years is to fight the latest attempts to evict him in the High Court.
Mr Haw sleeps in Parliament Square and sometimes uses a loudspeaker
Laws requiring all demonstrations within a half-mile zone around Westminster to have police permission come into force on 1 August.
Unauthorised protesters like Brian Haw, 56, could then be removed or arrested.
But Mr Haw, from Worcestershire, will argue that as his protest began before 1 August, the new law does not apply.
He said: "For centuries, British citizens have had the right to protest outside the mother of parliaments. Now this is to be left to the diktat of the police."
The new measures, part of the Serious Organised Crime and Police Act, effectively ban all spontaneous protests near Parliament.
They were specifically aimed at removing Mr Haw, as some MPs have complained that his outbursts on a loudspeaker are a distraction, and his numerous placards an eyesore.
He has already gone to the High Court to successfully fight off an attempt by Westminster Council to evict him.
Since he has been in Parliament Square, where he sleeps under a plastic sheet, other spontaneous protests have caused controversy, such as last year's clashes between police and pro-hunt campaigners.
Now all demonstrations will need police permission, a move the Home Office says puts protests on the same footing as processions and will protect the rights of people working in Westminster.
But critics say the half-mile wide zone, in which police can set time limits on protests and ban loudspeakers and placards, is too big and a "contempt of people's right to protest."
Mr Haw's solicitor David Thomas said the Act did not cover demonstrations which started before 1 August 2005.
"If Brian wins this case, the new system will remain in place for everyone else.
"However it will be susceptible to a human rights challenge, as it strikes at the heart of the right to peaceful protest," he said.
The case is due to be heard at the Royal Courts of Justice on 26 July.