Ithaca Energy, a North Sea oil and gas producer, has entered into an exclusivity agreement with Eni to potentially acquire its UK upstream assets. This deal comes as Ithaca Energy's annual profit has declined due to the impact of the UK windfall tax. The company has been given a four-week window to make an offer for Eni's assets, which include fields recently acquired from Neptune Energy. The talks between Ithaca Energy and Eni are described as 'advanced'.