It might depend on the field, but in Math/CS at a number of good unis, the standard path is a 4-year integrated MSc (you get a BSc after 3), then apply to PhD.

It might depend on the field, but in Math/CS at a number of good unis, the standard path is a 4-year integrated MSc (you get a BSc after 3), then apply to PhD. It is possible to do the MSc over 5-6 years and spend some time working, whether in parallel with studies as a teaching assistant, or taking a term/year out to get some industry experience. But in terms of credits gained, an MSc is 4 years net of studies.