Iain served as the General Secretary of the Labour Party from 2011-18, moving from the position as National Political Officer of the GMB Union. He has a long history of organising in both the Labour and trade union movement.

He grew up in the West coast of Scotland, he began his involvement in political organising as President of the Student Union at Dundee Institute of Technology in 1991, now Abertay University.

Iain is currently one of the Deputy Speakers in the Lords.