The ambitious rail scheme would take passengers further than Crossrail but opponents say the original London rail scheme must not be scrapped.

A £13.2bn cross-London rail scheme taking commuters from Paddington to Guildford in only 45 minutes has been unveiled by ex-rail boss Dr John Prideaux. The Superlink train service would follow the same central London rail route as Crossrail but would extend far beyond the suburbs to towns such as Cambridge, Ipswich, Guildford and Reading.

The rail scheme is backed by City finance house Babcock & Brown and is headed by Prideaux. He said that Superlink would carry four times as many passengers as Crossrail helping it to cover costs. He claimed like Crossrail that it could be completed by 2012.

Dr Prideaux said: “We think the building of a new east-west railway is too big an opportunity to be allowed to go wrong. Our scheme serves the planning needs and traffic patterns of the 21st century.”

He called on the government to “think again” about the Crossrail project, which he said would depend on billions of pounds of taxpayers money.

Superlink director Chris Stokes claimed that a fleet of air-conditioned state-of-the-art trains would cut journey times from Stanstead to Heathrow by 40 minutes to an hour.

The proposal was dismissed by Railway Forum director-general Adrian Lyons. He said: “Crossrail has the backing of a uniquely wide range of stakeholders. To now suggest is should not go ahead and we should place our faith in a concept, that is, at best, in the earliest stages of development and will cost more, is just not an option.