The review will look at five of Network Rail’s strategic routes, north and west of London: Chiltern, East Coast, West Coast, Great Western and Midland Main Lines.

Iain Coucher, Network Rail’s chief executive said: “By 2025 many lines will be full up, especially those running to and from the north and west of London. This will happen even after we have implemented the investment to boost current capacity.

“With popularity for rail growing, we have to start planning for the medium- and long-term future today. We have to see how we can meet the capacity challenge and see what solutions – including potentially, that of new lines – are deliverable and affordable. This review, working in partnership with other players in the railway industry, will kick start this process.

In the last decade passenger numbers have soared by 40% with 1.13bn journeys a year – the greatest number since 1946 – when the network was twice the size. Today around 22,000 services run on weekdays – up from 17,000 at the time of privatisation. In that time too, the amount of freight carried has rocketed by 60%. All credible current projections point to similar growth over the next decade. Also, punctuality has improved to a point where 90% of services arrive on time.

Network Rail has launched a tendering process to appoint a consultancy to carry out the study.