Slaughter and May, Allen & Overy (A&O) and Herbert Smith Freehills (HSF) have all advised on the £2.3bn sale of the Green Investment Bank (GIB) to Australia's Macquarie.

The long-running sale process dates back to 2015, when former Chancellor George Osborne announced that the government was planning on selling its controlling stake in the bank, which was set up in 2012 with £3.8bn of public funding.

The bank was founded to invest in environmentally friendly sectors of the economy for which there is a lack of support from private markets, such as renewable energy, carbon capture and storage, and renewable heat generation.

The sale closed today (20 April) in the face of political opposition from the Labour, Liberal Democrat and Green parties, after surviving a judicial review from unsuccessful bidder Sustainable Development Capital earlier this year.

Slaughters has been acting as lead adviser for the GIB, with the magic circle firm's team led by corporate partner Nilufer Von Bismarck, alongside competition partner Isabel Taylor, who advised on state aid matters.

HSF, meanwhile, is advising the Secretary of State for Business, Energy and Industrial Strategy with a team led by corporate partners Stephen Rayfield and Gavin Davies.

Australian bank Macquarie is being advised by A&O, which is fielding a team led by infrastructure partners Richard Evans and David Lee.

A&O also advised Macquarie as an interested party in the judicial review brought by unsuccessful bidder Sustainable Development Capital. Andrew Denny, the firm's head of UK public law, led the A&O team on the litigation, while Withers commercial litigation partner Andrew Wass acted for the claimant.

The defendants, the Secretary of State for Business and UK Government Investments, were represented by the Government Legal Service, with senior lawyer Sita Egole taking the key role.

Clifford Chance (CC) also played a role on the sale, acting for the lenders to Macquarie with a team consisting of banking partner Michael Bates, derivatives partner Anne Drakeford and corporate partner Amy Mahon.

Last year, Macquarie led a consortium that acquired a 61% stake in National Grid's gas distribution arm in a deal that valued the business at £13.8bn. CC and CMS acted for the consortium on that deal, while Linklaters advised National Grid.