The taxpayer was left £2.3 billion out of pocket when the government sold its 40% stake in Eurostar earlier this year, according to the National Audit Office (NAO).
The NAO also said the Treasury could have missed out on £743 million worth of dividends in the future. The report indicates that the government wanted rush through the sale before the general election.
The government sold its Eurostar stake for £585.1m to a pension fund in Canada. The Treasury also gained £172m when the company bought back shares.
But over the years the government held a stake in the cross-channel rail service, it invested more than £3bn, £2.3bn more than it recouped from the sale.
The National Audit Office did suggest that if the government had sold its stake later in the future, it would have gained a much higher price. Eurostar has a number of new trains on order and is set to launch new routes to the south of France and Amsterdam over the next two years. And the NAO believes new trains and new services would have resulted in a higher share price.
Amyas Morse, the head of the NAO, did describe the sale as 'effective' and "value for money", but stressed that the government could learn from the sale in the future.
“This case illustrates some general lessons for government as it embarks on an unprecedented asset sales programme forecast to exceed £62bn over this Parliament,” he said.
“These lessons include: the need for detailed business cases in support of the decision to sell; objective and robust valuations to decide if, and when, to sell; and getting good value from advisers.”