AFP, LONDON: Rolls-Royce, the British maker of plane engines and other power systems, roared back into net profit last year, largely as the pound recovered, the company revealed yesterday.

Profit after tax struck £4.2 billion ($5.8 billion, 4.7 billion euros) in 2017 following a net loss of £4.0 billion one year earlier, Rolls said in an earnings statement.

While the plunge in the value of the pound in the wake of Britain's 2016 vote in favour of Brexit helped many exporters, Rolls-Royce was forced to book a charge of £4.4 billion that year as it hadn't hedged against such a move.

The firm's hedge book showed a gain of £2.6 billion last year.

Stripping out exceptional gains and losses for Rolls during the past two years on foreign exchange factors, the company on Wednesday added that underlying pre-tax profit jumped by a quarter to almost £1.1 billion in 2017.