It has stood on George Square longer than any other building, its Victorian heart unchanged for generations.

But now the Millennium Hotel - better known to most Glaswegians as the Copthorne - has announced dramatic plans to expand skyward in to a "futuristic" extension.

Owners Millennium & Copthorne Hotels say they have been forced in to the move thanks to two equally dramatic developments now set to go ahead, whether they like it or not.

The first is the multi-storey car park directly behind them that has already received outline planning permission as part a council-backed scheme to turn Buchanan Galleries in to a supermall.

The second is equally significant revamp to Queen Street station that will see the hotel lose more than 50 rooms as an existing 1970s extension is bulldozed.

So the new design - although still to be formally unveiled - will both replace the rooms lost and hide the giant parking lot.

In doing so, it will change the skyline of the city's premier civic space forever.

A spokesman for Millennium & Copthorne Hotels said: "The proposed car park will loom over the hotel building, overshadowing George Square.

"We have now lodged a planning application with the City Council which seeks to address this problem.

"The application proposes total refurbishment of the property, replacing the bedrooms which are being demolished, and providing a futuristic design solution that will mask the gable end of the car park."

The Millennium's managers have already objected formally to compulsory purchase orders which paved the way for the planned Buchanan Galleries supermall.

The business, among other things, said it feared gridlock on George Square if the 1700-space car park was built.

The new parking lot is being built to replace a bigger facility currently on the other side of Cathedral Street, which is to be turned in to shops under the £400m project.

Buchanan Galleries developers already have basic outline planning permission but have not finalised the look of the car park.

Sources insist they will do their best to make the lot fit in with its surroundings and stress that such structures don't have to be ugly.

The car part park, centred on gap site on Cathedral Street and North Hanover Street, is understood to be as high as a normal 10-11-storey building.

Millennium & Copthorne Hotels have already shown their plans to the city council, to Buchanan Galleries owners Land Securities and to Network Rail, which owns some of the land the extension would be built on.

The hotel chain believes it could complete its expansion at the same time as both the supermall and the station are finished around 2019.

Clive Harrington, M&C's senior vice president for Europe said: "Our proposals will result in a better customer experience, within an attractive, integrated and modern development in which Glasgow can take pride.

"We look forward to engaging further with the City Council and hope that this fully-integrated development can be delivered in a timely manner to the benefit of all stakeholders."

Investment in Buchanan Galleries of £400m will come on top of another £120m at Queen Street, which will be seamlessly linked with the mall.

The Millennium Hotel is not officially part of the "Buchanan Quarter", the mall development officially backed by public money under a controversial Tax Incremental Finance or TIF deal.

Hotel owners said they would be making a "significant" investment in the property but were not more specific.

Network Rail and Glasgow City Council both confirmed they were aware of the plans.

Buchanan Galleries, meanwhile, insisted their car park would not be an eyesore. Nick Davis, its development director, said: "The final exterior design of the car park is currently being progressed in close consultation with stakeholder and will utilise high quality materials to reflect the rest of the Buchanan Galleries development and present a seamless link to the redeveloped Queen Street Station."

The station expansion will mean the removal of the existing SPT headquarters, as well as the Millennium rooms currently above the main entrance in a grey concrete block.

The new-look Queen Street facade will mean that the station's Victorian glass canopy is visible from George Square for the first time in half a century.

People power has already effectively blocked council proposals to revamp George Square and local politicians are aware that any change to the look of the city's unofficial centre will be controversial.

Councillor Nina Baker, the Green who represents the area, said: "I think that every single building put up around George Square should be good enough to be listed in the future. "

However, Ms Baker fears that because the station is be revamped under transport laws, not local planning rules, that final decisions will be made in Edinburgh, not Glasgow.

She said: "My main concern about the station project is accountability and transparency and that the public will get a say."

The Millennium Hotel building dates from 1807, long before the 1842 station or any of the other structures on the square.

Initially a row of merchants' townhouses, including one occupied by legendary art collector Sir William Burrell, it was converted into a series of hotels in the 1860s, eventually becoming united in a single business, the North British Railway Hotel, as part of the station.