Unfortunately for the UK, its geology means there isn't a lot of pumped hydropower storage unlike France, which is the cheapest way to bank intermittent renewables. In the places where there is pumped hydro capacity like Coire Glas, the operators are demanding the government guarantee they would be paid today's (natural gas generated) price to go ahead with construction, which would completely defeat the purpose of energy storage.

And yes, letting nuclear power dwindle was a political choice, spurred by short termist bean-counter thinking:

http://www.stross.org.uk/charlie/old/rant/torness.html