Between 1920-22 he was briefly a member of the Communist Party of Great Britain, however, he was excluded from membership in October 1922 on the grounds of 'political unreliability'.

From there he would branch out into publishing, and establish many literary friendships (including H. E. Bates, Rhys Davies, T. F. Powys) and D. H. Lawrence.

At one point, when Lahr was in financial difficulties, his writer friends gathered a collection of stories together and published these as Charles Wain (1933).

He was married in 1922 to Esther Argeband,[8] (at that time Archer), whom he had met at the Charlotte Street Socialist Club.

In subsequent misfortunes, Lahr was convicted in 1935 on a charge of receiving stolen books and was sentenced to 6 months in prison.