Fellows-Prynne has gone by “mutual consent” and will be replaced on an interim basis by current non-executive director Willie MacDiarmid while the firm searches for a permanent replacement.

May Gurney issued a trading update today warning that it will “significantly under-perform its original expectations for the current year.”

May Gurney shares slumped 40% in early trading on the news.

The board has set-aside a £10m one-off charge to cover the costs of running down its Facilities Services division.

May Gurney is also facing “operational issues” with its optimised solutions waste and recycling contracts and “on-going difficulties” at the Scottish utilities business as Scotia Gas Networks reduces outsourcing.

Chairman Baroness Ford said: “In taking this action today, the Board has moved swiftly to deal with the specific operational problems that have emerged over the last few months.

“We are fortunate to have secured the services of Willie MacDiarmid to lead the business on an interim basis.

“His depth of operational experience will be invaluable over the next period as we move to secure a permanent CEO.”

The warning came as it emerged that May Gurney has extended payment terms to 60 days from 45 for materials suppliers on its contracts.

The contractor is also planning to cut its 4,000-strong supply chain.