A new filing with Companies House showed Cossell has stepped down as a director.
Cossell was chief executive of ISG for over six years until the end of 2021, when he stepped up to become vice chairman, supporting chairman and US billionaire owner William Harrison.
While CEO, Cossell was the architect of ISG’s transformation from a £1.3bn contractor in 2016 to a major player achieving peak revenue of £2.5bn in 2020.
He is among several top-level leadership changes at the business. At the end of last week, it emerged that present ISG chief executive Matt Blowers and finance director Karen Booth are also exiting the business.
The shake-up at the top saw former chief operations officer Zoe Price promoted to become new chief executive, with Andrew Page brought in as interim chief financial officer.
Several other directors are understood now to be in the process of leaving ISG.