The protest will raise fresh questions over security at the Houses of Parliament.
It is seen as a fundamental part of British democracy that people should be able to go there 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 buildings have been subject to increasingly tight security measures in recent years because of the threat of terrorist attack.
Security had also been reviewed and stepped up after previous protests, including a fathers’ rights group throwing purple powder at then prime minister Tony Blair, and anti-hunting ban protesters entering the Commons.
Liberal Democrat transport spokesman Norman Baker told the BBC: “It’s clearly worrying that they have been able to get on the roof…
“But having said that I can understand, in a sense, the objective of the protesters. We have had a sham consultation on Heathrow.”
Well yes: perhaps instead of kowtowing to the airlines who simply want the convenience of extending their existing facilities at Heathrow, the government might bloody well have to consider the will of the electorate as well.
As someone living in a house bought on the Hawke government promise of “no third runway” for Sydney Airport, and living with the aftermath of that promise’s shattering to pander to the airlines and the airport consortium, I cheer the British protestors on. May you have more bloody luck with getting a fair hearing than we did.