IT would mark one of the most dramatic interventions of the post-war era.

But the experts and officials behind a radical bid to transform Glasgow’s transport offering insist it is not only feasible – but necessary.

Blueprints unveiled today would see the creation of a comprehensive Metro system serving as much of the city as possible, as well as proposals to link the rail networks around Central and Queen Street stations using a new tunnel.

READ MORE: Plans for a Glasgow Metro network and Central-Queen Street tunnel unveiled 

Elsewhere, a major extension of Central station out over the Clyde would prepare it for the roll-out of high-speed trains – with the eventual aim of supporting a rail service between Glasgow and London with a journey time of less than three hours.

It is a hugely ambitious set of proposals expected to cost around £10 billion over two decades, or £500 million a year.

But the Glasgow Connectivity Commission, which has put forward the recommendations, insists they are on a par with similar schemes in other European cities and in line with current spending in Scotland, such as around the Queensferry Crossing and duelling of the A9 and A96 roads. It argues its vision would help generate £4.6 billion a year for the Scottish economy.

Professor David Begg, chair of the Commission, said it was easy to baulk at the scale of what is proposed.

But he said: “The proposals we have recommended here will deliver a step-change in Glasgow’s economic performance and drive Scotland’s ambitions to deliver stronger, sustainable, inclusive growth.

“They are bold, ambitious and transformative but we are also confident that they are achievable and the right response to secure Glasgow’s long-term economic prosperity.”

Council leaders announced the establishment of the Commission in 2017, with a remit to generate fresh ideas to transform Scotland's biggest city.

It is led by Professor Begg, one of the UK’s most prominent transport experts, and includes representatives from the Glasgow Chamber of Commerce, Scottish Council for Development and Industry, Transform Scotland and Virgin Trains.

In its second report, it argues for a transport overhaul, highlighting the sharp divide in economic opportunity according to access to Glasgow’s suburban rail network.

It insists the most “glaringly obvious” omission in the city is the absence of “the kind of comprehensive, modern rapid transit system serving inner urban destinations that just nearly all of Glasgow’s comparator cities have been busy building for the last 30-40 years”.

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Glasgow’s subway is the only underground in the world never to have been extended, while its tramway closed completely in 1962. However, many former rail routes remain intact and ready to be reused.

The report adds: “The asset value of this dormant infrastructure could be measured in the billions of pounds, and therefore Glasgow has a ready-made basis for enhanced rapid transit that most cities can only dream about.”

The first priority of any wider transport strategy, the Commission argues, should be creating a Glasgow Metro system, using parts of the existing heavy rail network as well as entirely new sections – including some running alongside roads.

Meanwhile, old, disused rail routes – such as the former Central Low Level Line via the Botanic Gardens to Maryhill – would be reopened.

The Commission recommends building a link between the airport and Paisley Gilmour Street station by 2025 as the first leg of a Metro line that would then be extended to connect Renfrew – the largest town in Scotland without a rail station – Braehead Shopping Centre and Queen Elizabeth University Hospital to the city centre.

Over the next two decades, this route could then be extended across the city.

Elsewhere, a “strategic intervention” is required to make Glasgow ready for high-speed rail.

The only credible option, the report suggests, is to redesign and revamp Central station. This would require, at the very least, the extension of the station over the River Clyde and the creation of a new southern entrance and concourse roughly on the site of the former Bridge Street station.

Meanwhile, the Commission advocates “plugging” the gap between Queen Street and Central stations to permanently rid Glasgow of the barrier “imposed by the separation of the city’s two main railway stations”.

This would involve delivering on longstanding proposals to construct a new tunnel linking the existing rail networks on either side of the Clyde.

The most straightforward option, the report argues, is for a tunnel to cut across the city centre, starting from the Shields Road area to the south of the Clyde and continuing north, before joining the existing rail network near Cowlairs. A new, two-platform underground station between Central and Queen Street would give access to the line.

This option would provide around 20 trains an hour across the city and transform rail services throughout Scotland’s central belt, while a new station at Cowlairs could be “the centrepiece of an extended major redevelopment area”.

More ambitious plans for “tunnelled junctions” on either side of the city centre could further revolutionise services, creating a “truly comprehensive regional express rail network”.

While the most dramatic proposals in the report focus on rail, it also suggests moves to prioritise buses on Glasgow’s motorways to improve journey times and reduce traffic congestion.

Meanwhile, it argues Scotland should "lead the way" when it comes to preparing for the shift to electric and self-driving vehicles. With fuel duty receipts expected to plummet, new ways to pay for road use will need to be found.

Susan Aitken, leader of Glasgow City Council, said the blueprint had the potential to boost economic growth and give Glasgow the competitive edge it needs to compete globally.

Mark Johnston, managing director of Glasgow Airport, said the "ambition for a city-wide metro system starting at the airport is forward thinking and could address some of the major transport issues facing the city region".

He added: “We agree with the Commission’s calls for the airport link to be delivered by 2025 which will require firm commitments from the relevant organisations. The airport looks forward to receiving further details.”