In the dark days that followed the fall of France a new volunteer fighting force was hastily improvised in England to wage a secret war against Hitler's armies. This force was called the Special Operations Executive (SOE) and its mission was sabotage and subversion behind enemy lines.

Sabotage meant blowing up trains, bridges and factories while subversion meant fostering revolt or guerrilla warfare in all enemy and enemy-occupied countries. On July 16, 1940, Prime Minister Winston Churchill ordered SOE to ‘set Europe ablaze!’sabotaged train

Most of the actions conducted by the Danish resistance were railway sabotage to hinder German troop and material movements from and to Norway. However, there were examples of sabotage on a much larger scale especially by BOPA (Borgerlige Partisaner, which translates as Civil Partisans). In all over 1,000 operations were conducted from 1942 onwards.

The Danish Resistance assisted SOE in its activities in neutral Sweden. For example, SOE, with Danish participation, was able to obtain several shiploads of vital ball-bearings which had been interned in Swedish ports. The Danes also pioneered several secure communications methods; for example, a burst transmitter/receiver which transcribed Morse code onto a paper tape faster than a human operator could handle.

In Norway SOE agents destroyed the heavy water plant at Vemork, ending the Nazi atomic bomb program.

In January 1946 SOE was disbanded forever.

source: http://en.wikipedia.org/wiki/Special_Operations_Executive