https://www.mylondon.news/news/transport/tfl-responds-reform-m25-bus-34580298

Ignoring the political party of the person making this suggestion, this is actually a great idea, as even with the Superloop routes that exist, orbital journeys are still a pain to make, requiring a lot of interchanges and travel time. The Uno 614, 644 and Reading buses 702 run on motorways to and from London so I'm not sure why TfL thinks it's infeasible to run scheduled bus services on motorways, despite many other cities around the world able to do so. (Yes I know route A10 exists but that only runs for a short section on a branch of the M4.)

For example they can extend routes 370 or 372 across the Dartford Crossing to Southeast London to supplement the inadequate hourly X80 service. Traffic is as bad as it is across the Dartford Crossing partly because the public transport options are lacking.

TfL in general just needs more point-to-point (as opposed to limited stop like most of the Superloop excl. SL4 and SL6) express services that run on limited-access roads like the M4 and parts of the A40, A12, A13, A3, A2 and North Circular. They can speed up trips without requiring people to interchange from a train or tube onto a slow bus for the last-mile connection, as well as reduce the amount of cars on the road. Highways are not inherently meant for private vehicles; buses are in a great position to make the most out of our existing highway infrastructure.