Right along-side the Palace of Westminster and Westminster Bridge sits the unusual yet inconspicuous building of Portcullis House. Few people realise what goes on inside or what it’s there for. It is virtually an extension to the Houses of Parliament linked by underground tunnels, and to neighbouring buildings by elevated foot bridges. (Portcullis House is the black building on the left in the image below).

The building has many offices for MPs of all parties on the upper floors, with committee rooms on the first floor which you will have probably seen on TV without realising. These are used for select committee meetings and similar – most recently seen in the background of the infamous apology from 4 bankers as a result of the Credit Crunch. On the ground level there is a very impressive atrium complete with real trees and water features and surrounded by cafés, restaurants and the Parliamentary bookshop. Beneath this there is a very thick slab of concrete to protect the building from the potential of tube bombs from the Circle and District lines of the new Westminster Station which sits directly below. Far below that lies the new Jubilee Line station. Thus if this building started at ground level it would actually come to the height of Big Ben’s clock face!

Did you know that this building was specifically designed to last more than 200 years, using dear materials such as aluminium bronze in the roof and walls, thus making this one of the most expensive office buildings in the world! It works out at about £1million per MP.

If you have a keen eye, next time you’re at Westminster tube station look for the direct tunnel link to the Houses of Parliament. The entrance is located inside the ticket barriers on the Circle Line level.