London’s transport network will grind to a halt due to overcrowding unless the Government backs Crossrail 2.

- This is the warning from London Mayor Sadiq Khan.

Without the new line running across the capital from south west to north east, Waterloo and Victoria mainline stations risk "rush-hour meltdown", the mayor said.

A report by Transport for London showed that without Crossrail 2, at least 17 Tube stations will buckle under crowding pressures.

It also warned that thousands of passengers arriving at Euston on HS2 phase 2 services could lose time saved on their journeys by having to queue for onward trains.

Mr Khan said: "Crossrail 2 is crucial. It's crucial to meeting our ambitious targets for new affordable homes. It's crucial to unlocking future economic growth in the aftermath of the EU referendum.

"It's crucial to ensure that Euston station keeps running smoothly when HS2 opens, and it's crucial if we are to prevent Waterloo, Victoria and many other stations from rush-hour meltdown.

"Half the cost of the project can be met through funding from London, but we need the Government to meet the other half if we are to avoid this unbearable strain on our transport network.

"Crossrail 2 is the answer to help the entire country, because when London succeeds, Britain succeeds."

Crossrail 2 would cost about £30 billion in 2014 prices.

It would run as far north as Broxbourne in Hertfordshire and as far south as Epsom in Surrey, passing through central London via places such as Tottenham Court Road, Victoria, Chelsea and Clapham Junction.

Construction could start in the early 2020s and the railway could be open by 2033.