BP has said third quarter profits slumped to £3 billion, down 50% on the same period last year.

The oil giant’s results for the July to September period a year earlier were boosted by crude oil prices reaching an all-time high of 147 dollars a barrel, but prices averaged around half that this time around.

BP, which has been on a campaign to turn around its poor refining performance during the past 18 months, has been buoyed in the period by major discoveries in Angola and Mexico.

Despite Tuesday’s sharp fall in profits, BP’s performance was well ahead of City expectations and share prices rose following the announcement.

BP also increased its annual cost savings target for the second time this year, to 4 billion US dollars (£2.45 billion) from the 3 billion dollars (£1.83 billion) forecast in July.