The sale has proved controversial, with environmental groups expressing fears that the impetus behind clean energy technology could be lost.

The government has sold the Green Investment Bank (GIB) to Australian finance giant Macquarie Group for £2.3bn.

Founded in 2012 by the then-coalition government, the GIB was designed to attract private investment in green energy initiatives.

The sale has proved controversial, with environmental groups expressing fears that the impetus behind clean energy technology could be lost.

However the government said the deal would provide “value for the taxpayer while ensuring GIB continues its green mission in the private sector”.

Nick Hurd, climate change and industry minister said: “This gives us the best of both worlds. We have secured fair value for the UK taxpayer. GIB has a well-funded new owner that is committed to the Bank’s green mission, with a track record of success in green investment and an ambition to grow the business.

“The UK will benefit from increased investment in our green infrastructure as we make the transition to a green economy.”

The government, which will retain around £130m-worth of GIB assets until they too can be sold, said under its new owners the GIB would become “the primary vehicle for Macquarie’s renewable energy investment in the UK and Europe, with a commitment to target £3bn of new green infrastructure investment over the next three years”.

A number of GIB assets will be moved into a new offshore wind investment vehicle which will be managed by the bank, which retain a 25% stake.

Investors in this investment vehicle will be long-term institutional investors Macquarie European Infrastructure Fund 5 and the Universities Superannuation Scheme.