The following are UK visa and passport requirements for people visiting the UK for tourist purposes:
UK Visa and Passport Requirements for Australian, Canadian, Irish, New Zealand, South African, and US Citizens: Passport required. No visa required for stays of up to six months.
UK Visa and Passport Requirements for Kenyan and Nigerian Citizens: Passport required. Visa and/or transit visa required.
Wherever you travel from, make sure your passport has at least 6 months validity left on it when you arrive in the UK.
UK visa and passport requirements are subject to change at any time, so be sure to check the website of your country’s embassy or consulate before you travel.