It dramatises the bombing of the East Dudgeon lightship by the Luftwaffe on 29 January 1940 and was designed to portray Germany as a barbaric enemy.

An opening narration explains the traditional understanding of lightships (stationary ships used as lighthouses) as neutral vessels during war.

While they are waiting, a momentary danger is encountered and dealt with: a drifting mine comes perilously close to the ship and the crew call for a minesweeper to destroy it.

As the attack intensifies, and the aircraft begin to drop bombs, the entire crew manage to escape the vessel on a lifeboat.

The Ministry of Information decided to use this event for propaganda purposes, to portray Germany as a barbaric enemy and thus encourage support of the war effort against them.

Central to this propaganda aim of the film is the idea that the German aircraft are violating the traditional wartime convention that lightships should be protected as neutral, as they are undefended ships that serve all vessels regardless of the nationality of their crew.

[2] Another propaganda theme supported by Men of the Lightship is that of sacrifices for the war effort being made by ordinary working class citizens.

[2] To support this end, the characters in the film are developed to show their everyday concerns and activities, including the upcoming wedding of one crew member, and the pet tortoise owned by another.

[6] The film's realism was also mentioned in a review in The Times, which stated that "the employment, not of professional actors but of men who might well have had such an experience ... turns out to be inexplicably a better means of attaining reality than any skilled imitation.

[8] The Australian Women's Weekly praised the film's realism, stating: "It is difficult to believe you are not watching the real lightship and its crew, so natural is the acting of the cast, so vivid the action scenes.

[10] In a survey of propaganda shorts conducted by Mass-Observation in July 1941, Men of the Lightship was one of the best rated titles, receiving only positive responses.