You know those crazy Dems, never let a good slogan, or a good crisis, go to waste. 
So what is this Keep Calm and Carry On thing all about then?
The Ministry of Information was formed by the British Government as the department responsible for publicity and propaganda during the Second World War. In late 1939 after the outbreak of the war, the MOI was appointed by the British Government to design a number of morale boosting posters that would be displayed across the British Isles during the testing times that lay ahead.
With a bold coloured background, the posters were required to be similar in style and feature the symbolic crown of King George VI along with a simple yet effective font. The first two posters, ‘Your Courage, Your Cheerfulness, Your Resolution will Bring Us Victory’ and ‘Freedom is in Peril’ were produced by His Majesty’s Stationery Office (HMSO).