Hoax perpetrated by fans of Glasgow Rangers FC on their rivals, Glasgow Celtic FC that made the entire Celtic support believe Rangers had fallen behind Celtic in the race for the 2009 SPL Championship title.
On the last weekend of the 2008/09 SPL season both teams had a chance of winning the title but Celtic had to win at home to Hearts FC and hope that Rangers did not win away to Dundee United FC.
With around 20 minutes gone Rangers were 1-0 up and Celtic were drawing 0-0 when a load roar went around Celtic Park with Celtic fans (and Celtic coach Neil Lennon and player Paul Hartley) believing that Dundee United had equalised against Rangers. This was soon proved to be no more than 'misinformation' as there had been no goal for Dundee United and Rangers went on to win 3-0 and claim their World Record 52nd League title.
After the event it came to light that the reason that the Celtic fans ahd thought that Dundee United had scored was down to a prank codenamed 'Operation Tango' which had been thought up by a fan of Rangers and hatched on various fan websites, most notably followfollow.com.
The Rangers fans who took part in the prank were all to send a text message to a Celtic supporting friend who they knew would be at Celtic Park at the same time, spreading false hope around the 60,000 Celtic support.
The incident has been immortalised as 'Operation Tango' and the youtube video of the incident has received hundreds of thousands of views and the story has been reported in the press all over the world including Italy and Holland.