PhDs in biomedical sciences in the UK have generally been expected to take 3 years. But 4 year courses are becoming popular, following the Wellcome Trust's initiative to provide an introductory first year for PhD students, with additional training in research methodology and an opportunity for students to do research rotations in several labs, before committing to a subject and a supervisor for their PhD.

See the Wellcome Trust website for reviews of their PhD scheme from the students' and supervisors' perspectives.