The sale to Macquarie is expected to take around two months, subject to regulatory approvals.
However, the sale, in which the Australian group will pay £2.3 billion for the bank, drew criticism yesterday. "This acquisition is underscored by Macquarie's decades-long commitment to the United Kingdom as an attractive place to invest, and is a clear continuation of Macquarie's pioneering role in the infrastructure sector and our commitment to the low carbon economy".
Nick Mabey, chief executive of E3G, a think tank that developed the idea of the green bank, said that it was "reckless" because it would dampen investment in clean energy projects, while Ed Davey, the former Liberal Democrat energy secretary, said that it was "environmentally irresponsible".
"It now makes sense to move it into the private sector where it will be free from the constraints of public sector ownership". "We need investment in the booming clean technology industry in the United Kingdom, for skilled jobs, fairer bills and a healthy economy to see us through the next uncertain few years and in to the future".
"It has shown, as it set out to do, that green investment can be both green and profitable", Hurd adds. When the deal is completed, Macquarie will be the owner of the GIB, according to a statement from the asset manager and USS.
The bank's brand will be maintained, and the new owners said they will utilise the skills of employees in Edinburgh and London.
Lord Smith of Kelvin, independent chairman of the Green Investment Bank (GIB), said the board had supported the decision to privatise the Government-backed bank as the best route to securing its long-term future and growing green impact.
In a statement, the MPs select committee, said: "he Green Investment Bank is a unique institution, and the largest green energy investor in Europe".
As part of the transaction, a number of GIB assets will be moved into a new offshore wind investment vehicle which will be managed by GIB, which will retain a 25% stake.
GIB will become the primary vehicle for Macquarie's renewable energy investment in the United Kingdom and Europe, allowing the bank to expand internationally.
However, the choice of Macquarie, referred to in some circles as the "Vampire Kangaroo", has enraged many, who fear that the bank's green intentions will be lost while investments already made will be stripped and sold off by the firm.
Commenting on the news, Greenpeace UK policy director Dr Doug Parr said: "At a time when the Government should be shoring up low-carbon industry for post-Brexit Britain, they have given away one of our key tools for advancing green technologies".
However, the sale has suffered strong opposition from politicians and green campaigners, who point to Macquarie's alleged track record of "asset stripping" its acquisitions and investing in fossil fuel projects around the world. The Green Purposes Company Ltd (GPC) which holds the special share, sought to downplay fears of a change in objective of the bank in its response to the news.
Although all the shares are transferring, the government is appointing independent trustees with the power to ensure it continues to have an environmental mission.
Macquarie has also committed to continue GIB's investment approach, targeting investments across all areas of the green economy and across all stages of the project lifecycle, including the critical phases of development and construction. The GIB would have been a good vehicle to do that and we are short of that now'.
"If the Government picks up its pace, the United Kingdom could be a world leader in renewable and green technology".