His warning comes as Defence Secretary Michael Fallon announced Britain is to station a “small number” of troops in the Baltic states in a further move to deter Russian aggression.
Mr Sawer said: “It is going to be quite hard to continue this campaign unless there is a degree of military co-ordination between the Russians and the West.
“You can’t really have two air forces fighting different campaigns aimed at different objectives over the same territory without the real risk of a clash.”
Read more http://www.express.co.uk/news/world/610780/US-Russia-military-showdown-INEVITABLE-MI6-ISIS-strikes


