You appear to have a habit of riding on M3. Second time in three months!
No, that was January 2020, and the M40! This time I was following the A30 (including right beside the M25 at Runnymede), and then the A303.
Despite hitting roadworks past Basingstoke and a diversion sign pointing me onto the motorway at the previous junction (J7), I double checked whether that was actually for me, and was able to continue along the A30 to Popham.
MT(E&W)R 1982 say this:
Da Law said:
Nothing in the foregoing provisions of these Regulations shall preclude any person from using a motorway otherwise than in accordance with the provisions in any of the following circumstances, that is to say—
(a)where he does so in accordance with any direction or permission given by a constable in uniform or with the indication given by a traffic sign;
So it's quite possible that I had an opportunity to
legally cycle on the M3 and I still didn't take it - other than crossing the A30 slip road and taking that photo.