BP reported a significant drop in the costs related to last year’s devastating Gulf of Mexico oil disaster in the first quarter as the UK oil group sought to rebuild its oil and gas exploration operations.

The company, which last week launched legal claims against three companies involved with the Deepwater Horizon drilling rig which blew up killing 11 men, said non-operating costs related to the Gulf of Mexico disaster were $384m in the three-month period to the end of March compared to more than $1bn in the fourth quarter. The total charge last year was $40.9bn.