Ashurst and Herbert Smith Freehills (HSF) have advised on the successful £18bn agreement to build the UK’s first nuclear power station in 20 years.

The agreement was reached between EDF and the China General Nuclear Power Corporation (CGN) during a visit to the UK from Chinese President Xi Jinping. EDF said that the total cost of the deal would be £18bn with CGN paying £6bn.

Ashurst is advising Chinese-state owned CGN with a team led by client partner Robert Ogilvy-Watson and head of utilities David Wadham. The firm is understood to have originally picked up the relationship through its alliance with Chinese firm Guantao and the duo have previously advised CGN together.

HSF is advising longstanding client EDF with co-head of nuclear Julia Pyke leading a large multi-disciplinary team.

HSF and Slaughter and May originally won roles advising EDF on its investment into Hinkley Point in 2013. However, last year EDF also turned to Clifford Chance antitrust partner Jenine Hulsmann to help win approval for a nuclear reactor subsidiary scheme from the European Commission (EC).

Clifford Chance is understood to be acting for EDF SA, the French state-owned parent of EDF’s UK business, on the Hinkley Point C deal.

The EC initially protested a £17.6bn subsidy put forward by EDF stating that the deal potentially constituted “illegal state aid”.

Investment in Hinkley Point also secured backing worth £2bn through the Government guarantee scheme. The scheme promotes investment in UK infrastructure projects by guaranteeing that investors are paid all interest and principal due to them.

The Mersey Gateway Project and the Thames Tideway Tunnel have both received backing under the scheme. General counsel Celia Carlisle helped secure the funding for both projects.

Hinkley Point is set to begin generating energy in 2025 although the agreement also sets up discussions to begin development of similar sites at Sizewell and Bradwell.