Rail bosses are being asked to justify spending £1.1billion on new trains with no toilets. A fleet of 65 high-speed trains has been ordered for the London commuter line Crossrail, due to open in 2018.
The £15 billion line runs from Reading in Berkshire to Shenfield Essex with connecting spurs to Heathrow Airport and Canary Wharf.
A further extension to Tring in Hertfordshire is also being considered by the government.
The project is designed to increase London's rail capacity by 10%. Each train can carry 1,500 passengers. But there are no toilets on board. And some Crossrail stations will also have no toilets.
Crossrail executives will be questioned by members of the London Assembly tomorrow.