A £20M loan that helped persuade Nissan to build its Leaf electric car in Sunderland is the latest Labour spending decision thrown into jeopardy by the new coalition Government.

A Treasury review of all spending commitments made in the run-up to the General Election will include the loan guarantee given to the Japanese carmaker by Lord Mandelson in March.

The move will alarm the company and the region’s MPs, who saw the Leaf deal as crucial to securing the plant’s future, as well as having the potential to create thousands of extra jobs.

When the loan was announced, it was seen as a key example of Labour’s new “industrial activism”, aimed at rebalancing the economy away from the City of London.

But, on Monday, the new Lib Dem chief secretary, David Laws, announced he was reviewing all “poison pill” spending commitments made by Labour in its dying days.

Other, much bigger car loans made to Ford (£379m) and Vauxhall (£270m) will also be reviewed, to assess if they represent value for money and are consistent with the new Government’s aims.

Treasury ministers are expected to seek advice from inhouse lawyers about whether the Government can renege on Lord Mandelson’s financial promises.

Two wind energy announcements – an £18.5m grant for an offshore wind test site at the New and Renewable Energy Centre (Narec) in Blyth, Northumberland, and the launch of the £25m Clipper facility in Newcastle, to build the world’s largest turbine blades – will also be reviewed.

The rethink is key to Chancellor George Osborne’s plan to curb Government spending drastically and to start paying Britain’s £163bn budget deficit immediately.

The Northern Echo revealed yesterday that the £464m Wynyard Park hospital project – to replace outdated hospitals in Hartlepool and Stockton – is under review.

School rebuilding projects in Darlington (£57m), Hartlepool (£90m), Redcar and Cleveland (£100m) and Stockton (£150m) are also being reexamined.

The urgent review will also re-examine a £56.7m scheme to overhaul bus services across the Tees Valley, given the go-ahead in March after five years in development.

Yesterday, the BBC reported that civil service chiefs lodged formal protests at some Labour spending decisions – including the “nuclear option” of demanding written instructions from their political masters.

Jonathan Baume, leader of the First Division Association union, said there was dismay at the use of public finances as the election loomed.

However, the Treasury review will not include the recent go-aheads for wind farms, such as at Dogger Bank, off the North-East coast.

The Department for Business said the Crown Estates, which owns the British coastline, had handed out licences, rather than grants.