Faslane may well be unique but it IS in Scotland.
IF Scotland were to vote for independence and were to decide that they wanted no part in nuclear proliferation the rest of the UK would have, short of invasion, no other recourse other than remove them from a then self governing, sovereign state.
In fact I think the costs could, theoretically, be incurred by both parties by ratio meaning the brunt of that cost could fall on the remaining parts of the UK.
Where Engurland decide to stick them is neither here nor there.