Posted online at Companies House last week, the heavy loss for the year to October 2014 follows a slim £4.4m pre-tax profit the previous year.

Turnover was £787.8m, up marginally on the previous year’s £780.4m.

The firm said it had been hit by several poorly performing contracts at the UK construction business, although it does not identify which jobs have contributed to its losses in the accounts.

In a statement accompanying the accounts, the contractor’s directors said the “significant deterioration in the performance” of the firm was as a result of a “number of poorly performing contracts which have incurred considerable losses”.

The directors said market pressures - including “high cost escalation with a very stretched and limited supply chain”, particularly in London - and “weaknesses within our own operations” had contributed to “delays and cost escalations, resulting in losses on one project in particular”.

A spokesperson for Sir Robert McAlpine told Building said: “While the 2014 report and accounts show a loss for the year this was, to a great extent, due to one difficult project.

“Over the last 12 months the company has undertaken a thorough review of its governance procedures, has embarked upon a programme to increase efficiency across all aspects of the business, and has begun a significant upgrade of technology. It has also restructured its London division where, despite a very tough environment, it is delivering a number of high-profile and successful projects.

“The review and restructure work is already having a positive impact and the company has made an encouraging start to 2015 with some notable project wins throughout the UK totalling in excess of £600m.

“Sir Robert McAlpine Ltd remains committed to the highest standards of engineering quality, safety and sustainability in all of its activities and projects. The company is confident that this commitment to excellence combined with the business improvements will secure its future success as a key provider of complex building and infrastructure projects.”