Absolutely not a dedicated platform - the problem with the Trident replacement options was that it was assumed that we'd need some huge fleet of dedicated Airbus types and two brand new airfields.
All you need is a small, relatively simple physics package that could form the basis of a warhead for cruise missiles, a Storm Shadow derivative, and even a free fall bomb. Remember, the aim is independent NATIONALLY owned, autonomous deterrence - not wiping Moscow off the map using a weapon which ties us into US decision making and targeting.