THE Glasgow Subway is to remain closed for a further two weeks after renewal works hit "a number of issues".

Strathclyde Partnership for Transport (SPT), who operate the underground, said contractors had advised them of delays in completing the necessary tunnel upgrades.

There is now no official date for the Subway to re-open, but SPT said the works should be completed "about two weeks later than expected".

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Heavy rain over the past few weeks has reportedly complicated the project by flooding some parts of the network.

The Subway has been completely closed to passengers since July 2 but it was expected to re-open four weeks later on August 1. The delay means it will now be closed for a total of six weeks.

Replacement buses have been laid on instead, but passengers have complained that the service is unreliable.

The works - which involve a full replacement of the section in the tunnels known as "ramps and turnouts" - is being carried out as part of a £300 million modernisation of the Victorian era transport system.

London-based Colas Rail were awarded more than £6m by SPT to complete the works, plus an additional "risk and contingency" allowance and £500,000-a-year for "call off" specialist support for the duration of the contract.

In a statement, SPT said: "The contractor working on the essential renewal works of Glasgow Subway has now advised SPT that it requires extra time to complete the works.

"Despite assurances, Colas Rail has now confirmed that due to a number of issues they will not be able to hand back the system at the agreed time. We are working with the contractor to identify a new return to service date which they have estimated to be about two weeks later than expected."

SPT Assistant Chief Executive for Operations, Eric Stewart, apologised to passengers.

He said: “This is the most significant engineering aspect of the whole modernisation programme which is being built to last for another 40 years.

“This is a regrettable position and we are working with the contractor to pull back some of this lost time, as we endeavour to minimise any further disruption to our passengers.

“We apologise to all our passengers for this inconvenience.”