GLASGOW'S Pitt Street police headquarters is "almost certain" to be demolished, according to commercial property sources.

Hundreds of police staff will next week begin moving out of the 11,000sq ft office block - part 1930s brick, part 1970s concrete and glass - to a new base in the east end of the city.

Police Scotland, which inherited the complex from the old Strathclyde force, aims to strip the building ready for sale by the end of the quarter.

However, market experts believe the rabbit-warren of former admin offices and crime labs will be bought to be bulldozed to create a "hole in the ground" ripe for new build.

The existing building was valued at £12 million in 2008, just before the financial crash, then two years later the then Strathclyde force suggested a price of just £2.7m for the 1.3 acre city centre site.

Graham Waddell, of Johnston Waddell, said: "There will definitely be demand for this site. It will almost certainly be pulled down. I can't see anybody taking it and adapting it. It'll be a knock-down and a new development."

Brian Sheldon, regional director for Christie & Co, stressed the difficulties of selling a building configured like the old police headquarters.

Far more obvious buildings for conversion in the city centre have failed to find attractions. "Investors are more likely to be interested in a vacant site," he said.

Speculation has been rife for some time as to what Pitt Street could become. There are already budget hotels, office blocks and student accommodation in the area. Mr Waddell said a mixed scheme was possible.

He said: "What would appeal about the police site is the scale of it. Scale is what people are looking or now, not small gap sites.

"There are enough people now looking at Glasgow as a place for opportunities. I don't think there will be any issues selling it. The $60,000 question is what will they realise for it. I don't know."

Another expert, who asked not to be named, said: "There are already plans afoot for offices for 4,500 people in the area and demand is likely to be high. Investors will want a clear site."

The police do not need to make a great deal of money to make their move to their new HQ, the five-storey purpose-built facility in the Commonwealth Games regeneration area of Dalmarnock, effectively cost-free.

Their new building only cost £4.5m - thanks to a highly lucrative deal with regeneration vehicle Clyde Gateway, which effectively sees the force divisional HQ as a loss leader pulling other investment and jobs into the area.

The new building's actual value is believed to be closed to £24m.

Police have been eager to move out of Pitt Street, their home since 1975, for years.

Sir Stephen House, now chief constable of Police Scotland, first mooted the move in 2008, just before the financial crash, when he led the old Strathclyde force. Then the building was valued at £12m. Figures have varied dramatically since.

In 2010, Strathclyde suggested just £2.7m for the 1.3 acre site but said it could save more than £1m a year by moving to a better HQ.

Superintendent Donna Henderson, speaking in 2010, said: "This building is a money pit."

Police Scotland have already received some potential alternatives to demolition from Glasgow City Council and has been taking advice from the Scottish Futures Trust on how to get the best deal for the property.

The force's ruling civilian board, the Scottish Police Authority, will make a final decision on who to sell to.

A spokesman for Police Scotland said a rolling programme of staff transfers to Dalmarnock would begin on January 19 and would be completed by March. The force also has to dismantle equipment at the site, including radio masts.

He added: "All appropriate approvals are in place, preparations are under way, and the building will be marketed shortly."