They are hooligan / criminal firms. Its about getting one over the rival fans and the authorities. Man U had a firm called the intercity jibbers who would travel all over the UK and europe by sneaking onto busses and trains. They would then rob the local traders blind to fund there booze and drugs benders. They even had their own centralised travel group to make sure they could arrive en-masse and cause as much mahem as possible. Lots of ****ed up idiots being controlled by a small group of nasty and dangerous criminals. Jibbers are criminals who use football as a means to carry out their crimes.
Great book about it called "amongst the thugs" good read, scary stuff.
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