According to the UK Border Agency announcement of 29 November 2012, any migrant applying to enter or remain in the UK as the husband, wife, civil partner or fiancé(e) of a British citizen or a person settled there will need to show that they can speak and understand English.
This rule is intended to help migrants integrate into British society, to open up more opportunities, help prevent exploitation and allow them to benefit from, and contribute more to their communities.
Most applicants will meet the requirement by passing an English language test and supplying a test certificate with their visa application.
The current minimum level required is A1 of the Common European Framework of Reference (speaking and listening) which demonstrates basic English skills. From October 2013 level B1 of the Common European Framework of Reference will be required instead of A1.