Tycoon Jim Ratcliffe's Ineos is in line to become the biggest private enterprise operating in the North Sea after it agreed to acquire the oil and gas business of Dong Energy for an unconditional payment of $1.05bn (£808m), the company confirmed on Wednesday (24 May).

The sale agreement also includes contingent payments of $150m related to the Fredericia stabilisation plant, and up to another $100m subject to the development of the Rosebank field.

Dong's oil and gas operations yielded 100,000 barrels of oil equivalent per day (boepd) in 2016, and hold around 570m boe of commercial and potential oil and gas reserves across the Danish, Norwegian and UK Continental Shelves.

The acquisition and transfer of ownership is targeted to be completed within the third quarter of 2017, subject to the receipt of regulatory and other third party approvals.

On completion of the deal, 440 staff would be transferred to Ineos.

The move marks yet another impressive North Sea foray for Ratcliffe's outfit. In April, it agreed to buy the Forties Pipeline System (FPS) and its associated facilities, including the Kinneil Terminal, from oil giant BP in deal worth $250m.

Subject to regulatory approval, ownership of the FPS would give Ineos access to 40% of UK crude production. Ratcliffe recently moved his company's tax domicile back to UK from Switzerland, putting "faith", in his words, in the post-Brexit UK economy.

Commenting on his latest spending spree, the tycoon said: "Dong Energy's oil and gas business is a natural fit for Ineos as we continue to grow our Upstream activities.

"We are pleased to acquire this competitive, well run business, with its highly successful and experienced team, a strong portfolio of long life assets and a very good mix of existing production and developments across the North Sea."