http://www.bbc.co.uk/news/world-asia-pacific-13048131Taiwan use their motorways as airfields in simulated attack excercises...
Does the UK have the same ability?
I know the German motorway system was specifically designed (post WWII) to be used as emegerncy airfields in the case of an attack from Eastern Europe.
Many "rest areas" on the motorway have heavy duty electrical connections and military telephone connections hidden in them. The central reservation can be removed in minutes and an emergency runway installed in minutes.
Likewise, along the old East/West German border, there are tank-traps built into the roads. In an emergency, they can be activated and heavs steel poles come out of the ground, which will trap tanks trying to pass (normal vehicles wouldn't even get into the area, they would be written off, when this hit the first pole).