I wish I was clever enough to know the answer, but I do know some of the suggestions on Ferrari’s show this morning are not feasible, such as:
1 - calling 999 (“hold on, I’m just going to call 999 to check you are bona fide”).
2 - if there’s one available, hail a cab and jump in it.
3 - if there’s one available, jump on a bus.
4 - run away.
5 - buy the loudest rape alarm you can buy and set it off.
6 - scream.
Surely 2, 3 and 4 are tantamount to resisting arrest.
This guy was a rogue copper, and in 99.999999% recurring of cases, a copper would be going about his lawful duty.