Guy Fawkes would be proud, yes?

BBC Report

It is seen as a fundamental part of British democracy that people should be able to go Parliament to lobby their MP.

The public are allowed temporary passes to some parts of the building, but to get to most parts of the Palace of Westminster it is necessary to have security clearance or to be a guest of someone with clearance.
The "purple powder people", pro- and anti-hunting guys, and now anti-airport expansion folks scaling the roof.

Does the right of protest trump security measures?

Or, in these times of terrorism, should security prevail?