GLASGOW Subway will close down for a month next summer to allow modernisation work to be carried out.

Bosses at SPT had hoped the underground network would be able to continue operating while a £282million upgrade was carried out.

It will involve driverless trains and glass screens being installed at the edge of platforms.

But it has now been revealed the Subway will be out of action for four weeks from the start of the school summer holidays next year.

Independent industry experts have decided it is not possible to run a safe and reliable train operation while undertaking work on what is known as ramps and turnouts.

They allow trains to travel from a depot at ground level to the underground tunnels and to cross over between Inner and Outer circles.

They were installed almost 40 years ago and must be fully replaced to ensure reliable Subway services in the future.

The closure will affect 40,000 passengers a day but SPT says work will be carried out 24 hours a day to keep disruption to the minimum.

Buses will be run between stations on the Subway network to allow commuters to make their normal journeys overground and will operate for the same hours.

SPT chairman Jim Coleman praised staff for having carried out so much of the modernisation work without having to disrupt services.

And he pointed out during the last modernisation of the network in the late 1970s, the system was closed for two years.

He said: "It is always disappointing when we have to suspend a vital public transport service.

"However safety is not something the Partnership is prepared to compromise on and undertaking this vital upgrade when passenger numbers are at their lowest during the summer will minimise disruption for our customers.

"Although we are suspending Subway train services, SPT will take care of providing an alternative so there is no need for our loyal customers to do anything other than turn up at the station as they normally do, allow a little longer for the journey and leave the rest to us.

"We have vast experience in dealing with moving people for major events such as last year's Commonwealth Games and T in the Park."