The other train of thought it that 'Scally' was derived from a tough Irish-Liverpool family of the same name, the Scally family had a lot of sons who were always up to no good and thus the beginnings of the term Scally.
A scally is not from Birmingham, Leicester, Keighley, Corby, Brighton, Rotterdam or Dar es Salaam - Scallies are Scousers or Mancunian in origin, Scallies dress, act, talk and interact in a very individualistic way.
Scallies don't tend to work, they end to dress in sports/casual gear, they tend to be Irish Catholic in origin and they tend to smoke, drink take too many drugs.
Scallies are physically puny and tend not to be able to fight all that well - despite their violent tenedencies - they get round this by breeding pitbull terriers and walking them everywhere and carrying weaponary which they will use liberally.
Scallies tend to come from a long line of workshy, deviant, unemployable and violent bloodlines and DNA. Despite this some scallies make it to the big time in the sporting and musical fields - most noteworthy are the Gallagher brothers and Joey Barton - proper scalls them three.
The nearest cousin to the scally is the Glaswegian 'Ned'
both Celtic in DNA attitude and look (weedy, pale and they tend to smell)the scally is here for the time being so we all better get used to it - and that means buying a decent house alarm.
The female scally (dirtyious stinkius hair combed backious) has a tight combed back hair fag in left hand and a bram in the right (pram develops at the age of around 14)
The scally tribe congregate around shopping centres, food outlets and park benches, they mate for maybe a night after 5 minutes knowing one another and never speak again accept in greating 'oi ya fucking slag!' etc
The common scally should never be approched accept with a rifle and lots of ammunition!
cilla and chesney - coronation street
anyone who shops often (with stolen money) at JJb, JD sports etc
The scally will always dress in stolen sports-wear (e.g. Nike, Adidas, etc) and live in a run-down council house. Scallys are usualy seen loitering around sports shops, amusement arcades and fast food resteraunts - looking for a fight or something to steal.
The common sentence structure used by scallies can be closely compared to that of the American Redneck; often not being able to structure sentences longer than 5 words. The scally vocabulary range is always somewhat limited.
"fookin doh-dee looooyk!"
"lets rob sum ciggies fellas"