The extras in the fight scenes are people who were nearly exclusively those who are involved or were involved in the London underworld apart from certain stunt-men. after setting up the Leeds fight scene for most of the day the extras had had one too many beers got a little carried away and one of the stars got his head cut open with a punch. at that Cass and some others had to step in as to this day they work security at night clubs and are used to confrontations.
British heavyweight boxer Frank Bruno has cameo towards the end of the film, him and Cass were good mates, with Cass even saving him from confrontation on the streets once.
The film received a full blown (cast and crew) premier at Cineworld on Broad Street in Birmingham, UK. In order to accomplish this the cinema had to order a print of the film as they were not going to originally show it. Cineworld, Broad Street is itself the premier cinema outside of London in the UK. Other cinemas adjacent to Cineworld, Broad Street took note of this and ordered copies themselves, this had a dramatic effect on promoting the film. Accordingly the cinema run of Cass broke any and all expectations, pushing it to the very top of 18 rated movies that year in the British made film ratings.