There's a good argument to be made for requiring a fitness to govern test for anyone aspiring to public office at any level from local govt. upwards.
There used to be an exam for candidates for the Civil Service but any fool could, and often did, get into Parliament. Perhaps it's time to bring that back, at least for positions of administrative responsibility and require candidates for public office to pass it. Maybe retest periodically at age 70 & above.
PPE graduates should, of course, undergo substantial retraining before being allowed to even take the test.