There's a rumour that a gentleman known only as 'Booby dee' invented the term whilst describing his new girlfriend to a group of friends in the working mens club.
Deebo - fancy watching the footy tonight, daz?
Daz - aye, but this time leave ya bewer at home
Deebo - She took ma new car and ma credit card daz!
Daz - Sounds like your bewer needs a bullet, mate!
'my god, he was a right bewer'
for examples of bewers-take a look at mcfly (excluding tom)