Do UK universities collude in ways that inhibit genuine competition?

In July 2017 a former minister, Andrew Adonis, suggested that UK universities might be running a cartel: ‘There appears to be strong prima facie evidence of a cartel. It’s short-changing a number of students. They are paying for more than the actual cost of their degree.’ In this blog post we attempt to clarify the situation. Do universities compete? Are students paying too much? Is this because of a cartel?