Apparently the cost of football-related policing in Strathclyde alone hit £4.87 million during the 2007-08 season

The clash at the Liberty Stadium last season between Cardiff and Swansea cost South Wales Police a whopping £107,718.
That policing figure includes the cost of officers on duty on the day, but not the wider costs incurred such as the months of planning and gathering intelligence on potential trouble-makers.
Chief Constable Barbara Wilding has said the total cost to the force in terms of resources was in the region of £250,000!

The number of arrests at football matches are available on the web In the season 2006/7 195 Manchester United fans were arrested

Now I'm not really a football fan but I AM a supporter of the legal right to protest against racism and hatred of my fellow man so yes....

worth every penny!