Since the 1st of August 2005 you're no longer allowed to protest without permission outside the Houses of Parliament. MPs wanted to get rid of a protester named Brian Haw, who had been making a nuisance of himself in Parliament Square since June 2001, and apparently they also said that the noise made by protesters was distracting them from their work. I sympathise - it's tough being a politician in a democracy. You have to spend weeks convincing them to vote for you, and hours upon hours in your middle-of-nowhere constituency listening to them griping about the trials of their miserable lives, which for some reason they seem to want you to do something about. Can't they grant you a moment's peace to get some legislating done? Your country needs you making laws! There are still places without a single CCTV camera! Parents floundering in their futile attempts to raise children without a manual! Can't the whining protesters let you get on with the running of the country? Honestly, they have no idea of the workload. At the moment the police can only lock innocent people up for 28 days without trial, thanks to the pinko backbenchers. Don't they realise we'll never make it 90 if we can't hear the Speaker over their damned racket? It's for their own good.
Section 132 of the act is
here.
Wikipedia has a decent overview and some links
here.
There's an e-petition to repeal the act
here, but the dodgy grammar upsets me as it distorts the meaning slightly.
The vote on the relevent section of the Serious Organised Crime and Police Act 2005 was taken in the Commons on the 7th of Feb 2005. The summary of the vote is
here, including how your MP voted.