Supposedly originated from around the city of Liverpool in England (though to tar this wonderful place and its excellent folk with the following brush seems a bit unfair), scallies are quite simply the modern day yob or rebel, or indeed 'scallywag', from which the term is derived.
What motivates these people and what are their hobbies? They prefer to inhabit areas around public places, like arcades, shopping malls and leisure centres. But unlike other predatory species, scallies do not rely on camouflage or surprise. On the contrary, they are extremely obvious, usually decked out in tracksuits1 - the ones with the three stripes down the trouser leg and sleeve - and other neon-orange, green, pearl white or bright blue sports clothes, or in fact any clothes that really glare and hurt the eyes to look at.
Interestingly, many of them always speak only using the plural, often splitting from the herd and sidling up to a stranger to say, 'Haves yous gots anys moneys fors mes tos gos ands buys somes fagses2'. They appear to lack any common sense or logic and quite often it's possible to be approached by a single scally who will ask, 'Will you buys these fags of us so’s I can gets enough moneys to go and buy some fags.'
What the above quote demonstrates, among other things, is that there is no sense of individuality - the scally will always use the pronoun 'us' instead of 'me' - and again there is abundant evidence of the tragic tendency to use the plural at every given opportunity in every sentence.