Doctor Who

Sapphire and Steel

Dead Set

Misfits

In the Flesh

Day of the Triffids

Space 1999

A Clockwork Orange

28 Days later

Attack the Block

Shaun of the Dead

The Worlds End

Paul

 

Almost everything on this list

http://en.wikipedia.org/wiki/Category:British_science_fiction_films
http://www.britishhorrorfilms.co.uk/films.shtml