Southampton could be part of a new “electric spine” from the city centre to Yorkshire as part of government plans for the biggest investment in Britain's railways since the Victorian era.

Ministers will today unveil the £9.4 billion package of rail projects, including £4.2 billion worth of new schemes designed to kickstart the economy.

David Cameron and Nick Clegg will today seek to get the coalition to back the programme which will switch rail travel to more reliable and cleaner electric power.

By the end of the decade, they propose around three quarters of passenger miles to be travelled on electric trains, compared to 58 per cent today.

As well as boosting the economy the project is designed to ensure trains run more frequently and to time.

More than 850 extra miles of electrified line will be added to the rail network.

Plans include the creation of a high-capacity “electric spine” running from Yorkshire and the West Midlands to South Coast ports including Southampton.

This comprises an £800 million electrification and upgrade from Sheffield - through Nottingham, Derby and Leicester - to Bedford, completing the full electrification of the Midland Main Line out of London St Pancras and electrification of the lines from Nuneaton and Bedford to Oxford, Reading, Basingstoke and Southampton.

The plans also include the electrification of the Midland Main Line in what was hailed by Prime Minister David Cameron as the ''biggest modernisation of our railways since the Victorian era''.

Sections of the Midland Main Line from London to the East Midlands and Sheffied will also be electrified as well as part of the Great Western line from the capital to Swansea and the Welsh valleys.

Upgrades to the main East Coast Line from London to Leeds and Newcastle, as well as the first stage of a new 'varsity line' linking Oxford and Cambridge are also part of the plans.

Campaigners said this morning they feared the investment would be paid for by higher rail fares, while transport union the RMT said the projects announced today ''had been talked about for years''.

The announcement today covers the period 2014-19 and will be released in a dossier called the High Level Output Specification.