a highly politicised left his form of theatre which originated in 1920s europe

The playwright you’re most likely thinking of is Bertolt Brecht.

Here’s why Brecht fits the description:

Highly politicized: Brecht’s theatre was heavily influenced by Marxist ideology. He aimed to use theatre as a tool for social and political commentary, critiquing capitalism and advocating for social change.

Left his form of theatre: Brecht developed a theatrical style known as Epic theatre. This form was distinct from traditional theatre in its focus on audience alienation rather than emotional engagement. It aimed to make audiences think critically about the issues presented on stage.