Question to the Home Office:

To ask the Secretary of State for the Home Department, which countries' citizens (a) may and (b) may not enter the UK without a visa.

Appendix 2 to Appendix V of the Immigration Rules - https://www.gov.uk/guidance/immigration-rules/immigration-rules-appendix-v-visitor-rules - sets out those countries or territorial entities whose nationals or citizens need a visa in advance of travel to the UK for any purpose. Nationals or citizens of countries or territories that are not included in paragraph 1(a) of Appendix 2 do not need a visa in advance of travel to the UK as a visitor or for any other purpose for less than six months.