Radio 4 had an interesting piece on 'BH' (0900 this morning) by ex-Moscow correspondents Bridget Kendall and Brian Hanrahan.
http://www.bbc.co.uk/radio4/news/bh/
go to 'listen again' and the piece starts at time 21mins 40secs.
They suggest (at time 26mins30secs) that the only reason the Russians stopped sending Bears et al to test our alert systems is that they couldn't afford the fuel. Now they can afford it again.
airsound