Rok's finance director has resigned after an internal investigation into the group's M&E business cleared him of any malpractice.
Ashley Martin was suspended in August after “serious failings in the financial controls” of its Plumbing, Heating and Electrical (PHE) division were discovered.
Rok's share price plunged 50% following the news, and its PHE business was subsequently restructured at a cost of £6.8m.
However, after completing a review, the firm said it had “concluded that the problems in the PHE business were due to a scaling back of sub-contracting work from the private housing sector and a combination of weak operational, commercial and financial controls within that part of the business.”
It added: “The actions to resolve these issues have already been taken by management.”
Following the completion of the investigation, Rok lifted the suspension of Martin, but the finance director has decided to resign and will leave the business after a short handover period.
A statement from Rok said: “The board wishes to emphasize that Ashley has never been accused of wrongdoing nor have our investigations revealed any evidence of any malpractice. The board finds it regrettable if there has been any damage to Ashley's good reputation by any speculation outside of the Company to the contrary.”