Suggesting mandatory vaccination for a vaccine not even ready or fully tested is a slippery slope, not to mention a logistical nightmare. I believe Anthony Fauci in the US has already spoken against the idea. Imagine forcing people to take a vaccine that subsequently causes some serious problems, you would have nothing less than civil unrest as a result. And if even the vaccine turns out to be safe, how do you begin to prioritise? Mass vaccination of tens of millions of people would take months I'm sure, so what happens to those at the very bottom of the priority list. Do they become second class citizens, the "unclean" until it is their turn.
I know the idea appeals to some of the more authoritarian types on here, but what might seem to work in the sanitised RUK environment may well not work, even have serious ramifications out there in the real one. Its so utterly obvious what the plan should be if a vaccine gets licensed for general use, those most at risk and those caring for them must be the priority. Because they work & live in the environments that are by far and away the most likely sources of spread. Thereafter once this is complete the vaccine be offered to the rest of the general public in a series of rollouts based on risk.