The rest of the £41.5m cost will be funded by operator Strathclyde Partnership for Transport.

SPT chairman Jonathan Findlay said: “SPT has been pushing ahead with work to deliver a fully modernised Subway system and this pledge will make sure our vision for a network fit for the future is realised.

“Massive changes are coming down the line for the Subway and we’ve already committed millions to station upgrades, new escalators and smart card ticket technology as well as behind the scenes repairs to tunnels and track beds.

“Tendering for the new bespoke ‘driverless’ trains and signalling that could improve how often our trains run has already begun and we’ve received submissions from world class firms.”

Modernisation work is under way at Hillhead Station in Glasgow’s west end and is due to be completed towards the end of this summer.

Similar work will soon begin on Partick (lower) and Kelvinhall Stations, with Ibrox next on the list. All three will be completed by the time Glasgow hosts the Commonwealth Games in 2014.

SPT is also looking at installing lifts in some stations with Govan in particular (to link in with the new planned Fastlink bus service and the new Southern General Hospital) and St Enoch (key for the city centre) being examined.

SPT has pledged to keep the Subway operating throughout all refurbishment works and the majority of modernisation works should be complete by 2020.