Australian bank Macquarie is tipped to acquire the state-owned Green Investment Bank in a £2 billion privatisation deal.

The controversial sale of the Edinburgh and London co-headquartered bank could still be sold a UK-based consortium, but Macquarie is said to have made the highest offer.

Sources say it will be for ministers to decide whether to maximise value by accepting Macquarie’s bid, or retain ownership in British hands through a consortium including the Pension Protection Fund, Lloyds Bank and Sustainable Development Capital.

The bank was set up in 2012 under the chairmanship of Lord Smith to provide billions of pounds to kickstart major renewables projects. So far it has committed £770m of its own capital and secured £3bn in partnership with private investors.

The privatisation process was launched in June 2015 by the former business secretary Sajid Javid.

The government will hold a “golden share” to protect its green credentials.