Today {2011}, the threat to our country, indeed to many countries, comes from the Islamist extremists.  One hopes that the Government has a plan to address this problem, although it is apparent that individual organisations do face-up to this threat {BAA etc} and the rest, Government and police etc., react to events as they occur, how else {?} and all too often too late, regrettably. The police in particular have an almost impossible job, and with other front-line emergency services, are to be commended.

Back in the 1960's things were different and the threats were from aggressor countries and cataclysmic if carried out. These times were called the "Cold War" period and the perceived enemy were the Communist Regimes, chief of which was Russia. 

This file, marked "TOP SECRET" is a British Government file, endeavouring to predict the enactment of a threat and the national reaction to it led by the Central Government.

Worth a good read. 1960 the threat to the UK and civil defence.pdf