As for momentum. It's simply a new name for the usual suspects who have been protesting (and clearly not really wanting to be in power and accountable) since the '70s IMHO.
Surely the new leader of the Labour Party is also nothing more than a protester from the 1970s. A little old man with a satchel will never be an effective leader of the United Kingdom because once in power he would have nothing to protest about except himself.