ENERGY company BP and exploration firm BG Group have agreed one of the largest North Sea asset swaps in recent history.

The two companies are switching shareholdings in several fields in a deal that will leave their overall North Sea presence broadly the same.

Jon Wormley, BG's vice-president UK and Ireland, said the complex swap was "mutually advantageous".

BG is increasing its stake in the Neptune gas field it already runs off the coast of Lincolnshire and is taking a 75 per cent share in the Atlantic gas field which lies between two of BG's existing developments 100km off the coast of Aberdeen.

BP's side of the bargain is £21.5m in cash and minority stakes in a large number of oil fields as well as the SAGE pipeline running into St Fergus, Scotland.

A spokesman for BP said the assets were a "better fit" for the group than those it was swapping under the deal.

BP sold £201m worth of assets in the southern North Sea to FTSE 250 firm Tullow Oil last year following its purchase of US group Amoco.

Mr Wormley said: "BG and BP have achieved a formula that will greatly benefit both companies from a strategic as well as an operational viewpoint.

"It proves that determination, creative thinking and willingness to cooperate can lead to mutually advantageous swaps in the UK Continental Shelf."

BG last week reported a two per cent fall in first quarter headline earnings, to £133m, following the drop in energy prices earlier this year.