Its a difficult one. Imperial only has 110 undergrad programs, LSE even less. For LSE they need very few world class staff to teach 30-40 odd courses often of very similar natures. Similarly for Imperial. UCL and Durham have far more courses, and are therefore required to source many more lectures of the same stature across a far wider range.
At Undergrad they are broadly the same, beyond that its hard to classify just a university as different studies, even within departments will vary. Some may be pretty average all round but conduct world leading research on XYZ.
Its irrelevant for most people. I don't know of a single business that doesn't have those unis and more in their recruitment list.