The Dutch construction group said the falling pound accounted for more than half of the fall in first-half revenue which slipped 3 per cent to £916m compared to last year.

Reporting an otherwise good first half performance in the UK, Rob van Wingerden, CEO of Royal BAM Group, added that BAM had undertaken a thorough assessment of the implications of Brexit, and saw no material effect in the short term.

He said: “Since the Brexit vote, the only effect on BAM has been the translation of the weaker pound. Our UK order book is solid and we will maintain our tender discipline. We are monitoring new order intake closely and will adjust our operations if required.”

The UK is the BAM’s second-largest market after the Netherlands and accounted for 31 per cent of the revenue in 2015. The fall in the pound reduced the reported revenue from BAM Construction and BAM Nuttall by around £55m.

As a result of the improved trading performance UK group margins were restored to 1.7 per cent compared with just 0.3 per cent the year before.

Much of the profit growth was driven by BAM Nuttall and PPP activities after BAM Construction suffered small losses on closing a few projects.

The combined UK order book stands at £2.3 billion, with virtually all forecast revenue for this year secured.