A socialist activist for over forty years in Scotland, London, and Sudan, Bonnar has wide-ranging experience in the trade union movement and community politics.

At some point, Bonnar served on the editorial committee of Marxism Today,[4] a theoretical magazine generally seen as the standard-bearer for the "reformist" wing of the CPGB.

During his time as an aid worker in Sudan, he was an active member of the then-legal Sudanese Communist Party in Darfur and Khartoum.

[1] In 1996, he was a founding member of the Scottish Socialist Alliance (SSA) and stood as its candidate in Glasgow Anniesland in the 1997 general election.

[11] At the party's 2015 conference six months later, he stood down as co-chair and was returned unopposed as National Secretary, taking over from Kevin McVey.