When they were building the M25 motorway around London (about 120 miles for the loop) there were large sections that were built and not yet open to the public - much fun was had on fast motorbikes late at night! Though once the whole thing was open, it all got out of hand [0]. Having said that, back then you weren't risking serious jail term for high 3 figure speeds (on top of the risk of losing your licence, and potentially your life).

[0] https://www.classicdriver.com/en/article/1980s-motoring-exce...