St. Stephen's Hall
Upon entry, you pass through a metal detector, and are very thoroughly searched. You then proceed into ''St. Stephen's Hall'', where you are seated to wait for admission. A representative of the Sergeant-at-Arms gives you a slip of paper to write your name and address on.

Upon entry, you pass through a metal detector, and are very thoroughly searched. You then proceed into ''St. Stephen's Hall'', where you are seated to wait for admission. A representative of the Sergeant-at-Arms gives you a slip of paper to write your name and address on.
Check the official site before travelling; hours and prices can change.
More museums

Sir John Soane's Museum
Free, tiny, deranged — Soane's own house preserved exactly as he left it in 1837.

The Wallace Collection
Free national museum in a Manchester Square townhouse — armour, Boucher, the Laughing Cavalier.

The British Museum
Free, vast, civilisationally heavy — go for one room, not all of them.
Source: wikivoyage