Not sure I understand. If I drive to Heathrow today, will they put me in quarantine for two weeks?
No, but you are not allowed to enter the US, if you‘ve been in a county banned from entry 2 weeks prior to departure. So if you are based in France, you‘d have to actually stay and wain in the UK before you fly. If you‘re an American you can enter, but only if tested before (whatever this means... and you‘d have to find a plane too first).