Lonely Planet review
Officially called the Palace of Westminster, the Houses of Parliament's oldest part is 11th-century Westminster Hall, which is one of only a few sections that survived a catastrophic fire in 1834. Its roof, added between 1394 and 1401, is the earliest known example of a hammerbeam roof. Most of the rest of the building is a neo-Gothic confection built by Charles Barry and Augustus Pugin's (1840-1858).
The palace's most famous feature is its clock tower, aka Big Ben. Ben is actually the 13-ton bell, named after Benjamin Hall, who was commissioner of works when the tower was completed in 1858.
At the business end, parliament is split into two houses. The green-hued House of Commons is the lower house, where the 650 elected Members of Parliament sit. Traditionally the home of hereditary bluebloods, the scarlet-decorated House of Lords, with 763 members, now has peers appointed through various means. Both houses debate and vote on legislation, which is then presented to the Queen for her Royal Assent (in practice, this is a formality; the last time Royal Assent was denied was 1708). At the annual State Opening of Parliament, which takes place in May from 2012, the Queen takes her throne in the House of Lords, having arrived in the gold-trimmed Irish State Coach from Buckingham Palace (her crown travels alone in Queen Alexandra's State Coach). It's well worth lining the route for a gawk at the crown jewels sparkling in the sun.
When Parliament is in session, visitors are admitted to the House of Commons Visitors' Gallery . Expect to queue for at least an hour and possibly longer during Question Time (at the beginning of each day). The House of Lords Visitors' Gallery is also open to the public.
Parliamentary recesses (ie MP holidays) last for three months over summer and a couple of weeks over Easter and Christmas. When parliament is in recess there are guided tours of both chambers and other historic areas and on Saturday year-round. UK residents can approach their MPs to arrange a free tour and to climb the Clock Tower.