Tonight at 9.30pm on BBC2 a new television documentary, ‘Inside the Commons’ reveals behind the scenes parts of Parliament never seen by the public.

The Palace of Westminster has 1,000 rooms and three miles of corridors and is often referred to by insiders as Hogwarts.  Seasoned veteran Liberal Democrat Charles Kennedy admits to still getting lost in the building. The four part series goes onto the floor of the Commons chamber, allowing viewers to see exactly what MPs see during debates.

It took six years to persuade the authorities before they agreed to the series.  David Cameron talks about his dread of Prime Minister’s Questions;  “there isn’t a Wednesday that you don’t feel total fear and trepidation about what is about to happen. I think prime ministers have always felt that.”

There was opposition to the documentary from some MPs who have a “general hatred of the media” in the wake of the expenses scandal, and who made it clear they were against the project.

Sir Robert Rogers, the Commons clerk and chief executive (who resigned in 2014) deals with the the need to conserve the building and at the same time bringing its facilities, including communications technology into the 21st Century. “We’re trying to run a modern parliament in a Victorian building.”

The first episode of Inside the Commons is on BBC Two at 9pm on Tuesday 3 February and runs for four weeks.