Chancellor George Osborne has confirmed plans to sell the government's 40 per cent stake in Eurostar to help improve the public finances.

It is hoped the move will raise an initial sum of £300 million and contribute to around £20 billion the government plans to obtain from corporate and financial asset sales by 2020 - money that will be used to help pay off the national debt.

The chancellor came under fire from rail unions and the Labour Party, who warned that the sale of the service could suffer from the same problems that beset the privatisation of Royal Mail.

Shadow transport secretary Mary Creagh called for the National Audit Office to conduct a full value-for-money enquiry so that taxpayers "are not ripped-off again". 

The French state train company SNCF currently owns 55 per cent of Eurostar, while Belgium's SNCB holds five per cent.

Legacy Royal Mail pension assets, the uranium enrichment company Urenco, the income-contingent student loan book and further public sector wireless communication spectrum could also be put up for sale by the government.