The government and Network Rail are considering a £31bn proposal to build a network of 187mph high-speed railway lines that would boost the British economy and slash journey times.

New studies drawn up by Atkins, the engineering consultancy, show how developing the existing west and east coast main lines could see journey times from London to Manchester reduced to 74 minutes, London-Birmingham to just one hour, and London-Sheffield to 79 minutes.

Economic gains to the UK of £63bn far exceed the £31bn cost of building the network, says Atkins.

Atkins's report envisages that high-speed lines would run on the east and west sides of the country, going as far north as Glasgow and Edinburgh. They would replace most of the existing services and free up capacity for local trains.