Builder Laing O'Rourke out of the red with £33m profit

It draws a line under significant losses of more than £200m on a Canadian hospital project in the past four years.

Chief executive Ray O'Rourke said that the firm was forecasting a pre-tax profit of £39.6m for the six months to the end of September in its UK businesses, and that a gross margin of 7.6pc is being achieved by the company.

The business has orders of £7.6bn on its books. Widely regarded as Europe's largest privately owned construction firm, the London headquartered group employs 12,685 staff, including 2,000 in its Australian business, recently completing large naval projects and an expansion of Brisbane Airport there. In recent years, the firm has worked on London's Crossrail, new tube stations and other infrastructure, such as the English capital's £4bn 'super-sewer'.

Chairman John Parker said: "UK construction remains in a troubled state. A number of key lending banks have signalled their exit from the sector; thankfully, a few remain committed."

O'Rourke and his senior team have also negotiated a refinancing of the business in recent years, incurring millions in fees to external advisers.

In its Brexit risk assessment, the firm noted that 15.6pc of its UK staff are EU citizens, with whom it has worked extensively to understand their rights under all scenarios. It is assisting them in securing 'settled status'.

About 300, or just over a fifth, of the firm's European staff are understood to be Irish.

O'Rourke, a qualified engineer and pilot, added that he wanted to achieve industry-leading cost- efficiency, and was "concentrating on more complex projects in the UK - where we can engage early to drive compelling solutions - and major infrastructure projects in Australia".

The firm spent £30m on R&D during the year, and increasingly deploys the latest technology in its work, recently patenting a 'spotter' safety device that uses AI and computer vision to warn of people or objects in vehicle blind spots.

Two of the firm's female engineers featured this year in the Financial Times' 100 most influential women leaders in engineering in the UK and Europe list.

Separately, another Irish-owned UK construction business, Mayo man John Reddington's JRL Group, reported a record turnover of £539m in its accounts for last year, passing the £500m mark for the first time, and booking a £31m pre-tax profit.

The firm employs more than 1,300 staff, and initially specialised in concrete frames and groundwork.

It now covers many aspects of construction work in and around London, and also hires out and sells tower cranes.