A compelling case for the first big electrification programme for 20 years will today be presented by the company that runs Britain's railways - a move that would cut rail costs and lead to faster, more reliable and cleaner journeys.

The Network Rail consultation will say electrification of much of the Great Western route from London to western England and Wales and of the Midland main line from London to Sheffield makes most sense. Neither project would need any government grant or subsidy.