To be legal in the UK, vehicles have to have a certificate of conformity, getting one is the responsibility of the manufacturer. Tesla have done that for their other models, but not for cybertruck. I assume that's because the have decided the costs of getting cybertruck compliant with UK regulations would be too high, or not practical.

That's a business decision made by Tesla, not victimisation of poor old Elon, whatever the Musk fanbois think.