BOLD plans to cover Scotland's busiest motorway stretch with a public park would be "exciting, international and doable yet very very expensive", one of the country's leading architectural expert has claimed.

Neil Baxter, secretary of the Royal Incorporation of Architects in Scotland, said the proposal to cover the M8 as it passes through Glasgow city centre would restore neighbourhoods such as Charing Cross and Anderston.

Mr Baxter compared it with a similar scheme around Barcelona's Olympic Village, designed by Glasgow expat David Mackay, which has been instrumental in the Catalan capital's huge popularity in recent years.

The idea has also been given a guarded welcome by opposition leaders on the city council, who questioned the appetite of the current administration to follow through on it.

The most radical of 80 projects to rehabilitate the area around Charing Cross, Sauchiehall Street and the Garnethill district, the plan involves a roof covering the sections of the M8 around the A-listed Mitchell Library, over which a public park would be built.

Although no timescales or costs have been attached at such an early stage, a report in front of the city council's decision-making executive committee next week makes repeated references to the oncoming need to upgrade the motorway infrastructure along the stretch.

Another proposal involves creating a "raised central garden" space by removing the existing slip lane, "thereby providing a new landmark green space at a key city centre gateway".

Mr Baxter said that while the decision to cut through the city with a motorway was vital at the time, the enclosure and creation of new public spaces would complete the work of almost 50 years ago.

He said: "Sadly unlike Barcelona we can't bring Glasgow to the sea but instead of motorway desolation we can create public spaces, bars, retail.

"Had the M8 not been built Glasgow would've seized up a long long time ago. They thought about the vital, not the cosmetic. This can follow through on that and restore the area to its full beauty and realise its potential."

He added: "For any city to make real progress the true architects have to be the politicians. They need to think about the public space, the built environment and make their city as good as it can be for the people who live there."

Susan Aitken, leader of the City council's SNP group, described the plans as "an innovative idea for a part of the city that has long needed a rethink".

She added: "It fits well with the SNP group's own ambitions for Glasgow's urban realm. But I am somewhat sceptical that the current administration have any intention of actually delivering on this.

"They've got a history of talking big on projects like this and noticeably failing to come up with the goods. If they are serious about it though, I welcome their conversion. The SNP group would certainly support further work to make this project a reality."

A covered motorway in Marbella, Spain, is also understood to have been an inspiration, while cities such as Utrecht in the Netherlands and Vancouver in Canada have recently announced similar schemes.

Much of the city council's plan for the wider area also borrows heavily from urban regeneration in Copenhagen, where whole areas have been made pedestrian and cyclist-friendly.

The report on the project states: "The uncovered M8 cutting contributes the negative qualities of severance, noise and air pollution, while the three-lane slip roads on either side discourage anyone from doing any more than scuttling through as fast as possible.

"The reality of infrastructure life cycles means that a decision needs to be taken soon about investing in replacing

elements of the existing motorway or altering it to the benefit of the city and the region."