The £1billion bill for Crossrail trains will now be footed completely by taxpayers after the government abandoned attempts to attract private funding.

A £350million public contribution towards the trains and maintenance facilities was originally planned for the new line from Maidenhead, through central London and out to Shenfield in Essex.

Crossrail will take over the current Greater Anglia service through Ilford, Goodmayes, Seven Kings and Chadwell Heath.

The government invited private bidders to fund the new trains in September but has now dropped the plan to “ensure” the project is completed on time.

Trains are due by 2014 ahead of tests in 2017 for the line to open to passengers in 2018.

A Transport for London spokesman said the funding plans were “always subject to achieving the best outcome for the project and Crossrail Ltd reserved the right to make changes to the procurement”.

The Mayor of London Boris Johnson said Crossrail will increase London’s rail capacity by 10 per cent.

He added: “Nothing must get in the way of this fabulous new railway and it is fantastic news that we can now crack on with buying the wonderful fleet of brand spanking new trains.”