The government's public private partnership plan for the tube would see delays of up to 20 years for improvements to London's most crowded underground lines, it has been claimed.

As Ken Livingstone won permission to seek judicial review of the plan on safety grounds, the government claimed that keeping the tube in the public sector would mean charging every London home £650 or increasing the price of travelcards by 50 pence a day.

The on-going conflict between the London mayor and Whitehall will go to court on June 12.