On 13 August 1961, the German Democratic Republic (East Germany) started building what became known as the Berlin Wall. This sudden development in the Soviet bloc caused Communist Parties around the world to come up with arguments to support this move by the GDR. Here is a pamphlet (probably) distributed by the Communist Party of Great Britain in the early 1960s to defend the Wall.
There is no authorship attributed on the pamphlet. If anyone knows anything more about this pamphlet, please let me know.