A Hoops fan replaced the Scottish flag above Glasgow City Chambers with a flag celebrating nine in a row. 

The prankster was videoed hoisting up a green and white flag with a large number nine by George Square. 

It is understood the flag was only kept up momentarily before the Saltire was flying high. 

The incident is being investigated by Glasgow City Council

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A spokeswoman said: "This is inappropriate. It should not have happened and we are investigating.”

Conservative councillor for Shettleston Thomas Kerr added that he was "concerned" to see the Celtic flag flown from the city chambers. 

He wrote: "Concerned to see a Celtic flag being flown from the city chambers this morning.

"Our civic buildings are there for all Glaswegians no matter which football team you choose to support.

"I have spoken to the Lord Provost who has assured me that this matter is being investigated."

It came after Celtic football club made its mark on the city to announce the release of their new adidas home kit. 

The club posted images of well-known Glasgow spots with 'One Decade In The Making 10.07' written in green letters.