Plans to sell off assets such as Ordnance Survey and the Met Office have been described as “Santa Claus economics” by unions.

The Shareholder Executive's review of how publicly owned businesses such as British Waterways, Queen Elizabeth II conference centre, the Land Registry and Royal Mint operate was apublished in Monday’s pre-Budget report.

Also to be examined by Standard Life chairman Gerry Grimstone, as part of the asset strand of the Treasury’s operational efficiency programme, are the Oil and Pipeline Agency and the Defence Storage and Distribution Agency.

Changes to their financial model could provide some of the £5bn extra savings that the government wants to see in addition to the £30bn that must be saved across public services over the 2008-11 spending review period.

The government has asked the Shareholder Executive to report back in time for the Budget in 2009.

Prospect deputy general secretary Dai Hudd warned that the privatisation plans, which have been mooted several times over the past two decades, risked jeopardising the quality of public services.

“On each occasion after thorough analysis privatisation was rejected because the loss to British industry and the public interest outweighed a short-term gain of a few million pounds.

“Any attempt to sell them off now would be economic madness. In the current climate the market value of these public assets will be way below their real value. It would be a case of sell in haste, repent at leisure.

“Government will face the justifiable anger of taxpayers if they see these national assets sold at bargain basement, credit-crunch prices. Even Santa Claus would flinch at such a giveaway.”