Stirling University's initiative is a step forward towards more continental style PhDs in the UK.
Years ago, I was informed by Aberdeen University that there are no statutory barriers to a thesis taking the form of a series of (previously published) articles. At present, I supervise one student who is on track to submit her thesis based on peer-reviewed journal articles. However, she can do it this way only because she is a part-time student.
Currently, UK funding restrictions stand in the way of article-based PhDs. The pressure on postgraduate students to submit within three or a maximum four years acts as a barrier, since it can take a considerable time to get the required four (or five) papers published. Most academics will have horror stories of papers appearing in print three or four years after first submission. A PhD student starting to write the first paper in the second year cannot afford to wait for the final academic paper to appear in print (or at least get accepted) four or more years later. So, although it is a good idea, at present it is probably a case of "one size does not fit all".
Edwin R. van Teijlingen
Reader in public health
Aberdeen University