Washington does it on our behalf.
If that's the case, invade France. Immediately.
No independent government choice of action? The UK, for it's own purposes, whether Allied solidarity, a hope for something in return, or even just thinking it was the right thing to do, made the choice to join.
Man up and take responsibility for your own government.
Otherwise, it's really gotta suck not being in charge of one's own destiny.
So, on to France with you now......