I don't like riding on B roads, let alone A roads, so a motorway is deffo off limits.
However, I will say that people driving on motorways should be looking a damn sight further up the road than the boot lid of the car in front, and if they were to adopt such observation as normal practice, then there's nothing 'unsafe' about cycling on the hard shoulder.
However, it's still illegal, and the 'cyclist' that did it is a knobber, on a par with the female 'knobber cyclist' that tried to ride into the path of a train a few weeks ago.
People are knobbers, be they drivers, cyclists, men or women.