Amec Foster Wheeler, currently working towards an agreed takeover by John Wood Group, would have lost even more money in 2016 but for the fall in the value of sterling, which substantially boosted the value of its overseas earnings.
"We continue to expect another year of decline in oil and gas activity in 2017 and for solar activity to reduce significantly from the record levels seen in 2016,” said chief executive Jon Lewis.
Revenue on continuing operations for 2016 was largely unchanged at £5,440m (2015: £5,455m).
The 2016 pre-tax loss of £542m was more than double 2015’s loss of £235m.
The company has struggled ever since Amec's £2bn acquisition of Foster Wheel in November 2014, just before their core oil & gas market began to stall.
A shareholder vote on Wood Group's takeover offer is expected in June. That deal values Amec Foster Wheeler at £2,225m.