Rolls-Royce, the British maker of plane engines, said Thursday that it plans to cut 4,600 mainly British management roles by 2020 in a vast restructuring that has already resulted in thousands of job losses. The London-listed company, whose engines are used in Airbus and Boeing aircraft, said the latest cuts would produce 400 million pound ($536 million) of annual cost savings by the end of 2020. Rolls has faced a tough trading environment in recent years on weak demand for its plane engines and marine power systems.

Although it roared back into profit last year, this was largely owing to a recovery in the pound. Rolls said the latest round of restructuring was expected to cost the group 500 million pound ($671.9 million). Rolls employs more than 22,000 staff in Britain, of which over one half are based at its U.K. operations center in Derby, central England.

In total, the company employs around 55,000 worldwide. Rolls had in January announced a major overhaul of its operations, reducing the number of core units and basing the remainder around civil aerospace, defence and power systems. At the same time, the company has said it would consider selling its commercial marine business, while in April, Rolls sold German division L'Orange for 700 million euros to U.S. group Woodward.