Woolf's resignation comes at a time when Mitie is in the midst of a cost-saving drive to revive its fortunes under Chief Executive Officer Phil Bentley, who took over at the end of 2016. Mitie reviewed its strategy and accounts after a string of profit warnings in 2016.

The collapse of rival Carillion and Interserve's slide into administration have hurt sentiment towards UK contractors and outsourcing groups, but Bentley has been optimistic that Mitie would emerge well placed from the shakeout.

Mitie, which provides cleaning, security and healthcare services, said Woolf would leave on Jan. 28. He joined the company in 2017.

"Paul has been hugely supportive in the turnaround of Mitie, bringing in new financial disciplines and helping restore investor confidence," Mitie Chairman Derek Mapp said in a statement.

Mitie, which manages and maintains London's landmarks, high- street buildings and homes, reported a rise in first-quarter revenue in July, boosted by new contracts and a recent acquisition in its security business, but said higher-than-planned costs weighed on profits.

(Reporting by Noor Zainab Hussain in Bengaluru; Editing by Rashmi Aich)