The Blackshirt was the official newspaper of Oswald Mosley's British Union of Fascists (BUF). The paper first appeared in 1933. From June 1939 it became the British Union News. It ceased the same year. The paper also incorporated the short-lived The Fascist Week (1933-34).
After the BUF launched Action in 1936, The Blackshirt became more targeted at committed fascists.
References
The Blackshirt Wikipedia(Text) CC BY-SA