Fadar Westminster ta kasance ne daga Gidajen Majalisar Landan da kuma Hasumiyar Tsaro, wacce aka fi sani da Big Ben. Da farko, yakamata ayi amfani dashi azaman masaukin masarauta, kodayake babu wani sarki da ya taɓa zama a wurin. An gina shi a gefen Kogin Thames.
Ginin misali ne bayyananne na salon Neo-Gothic. Daga baya, an yi gyare-gyare da fadada wanda aka yi amfani da salon Gothic a tsaye, don yin kwatankwacin wanda aka riga aka yi amfani dashi a baya a cikin Henry VII Chapel a Westminster Abbey.
Gidajen majalisa shine inda majalisun biyu na Majalisar Dinkin Duniya suke haduwa: House of Lords da House of Commons. Wasu daga cikin hasumiyar membobin Chambers suna amfani dashi azaman ofisoshi, gami da waɗanda aka adana daga zamanin da. Mafi girman duka shine Hasumiyar Victoria, wanda ke kudu maso yammacin fadar. A ciki akwai Ofisoshin Rijista na duka bersungiyoyin kuma, ƙari, a gindinsa, mashigar Masarauta zuwa fada.
Amma mafi shahararren hasumiya, wanda ke gefen arewa maso yamma shine Clock Tower. A ciki akwai babban agogo wanda ke da fuska ga kowane gefen hasumiyar. Kari akan haka, tana da kararrawa guda biyar, wadanda suke ringin abinda ake kira Westminster Chimes kowane kwata na awa daya. Mafi girman su, wanda ke yin saƙo a kowane sa'a, ana kiran sa Big Ben, kuma wanda ke da keɓaɓɓun kayan tarihi.