Professor Hobbs said the behaviour of doormen was mixed

Disorder is usually dealt with by door staff, and their methods can be rough and ready, according to a Durham University criminologist.

The study, by Professor Dick Hobbs, also highlights the emergence of a booming "Alcohol Economy" and an increasingly violent sub-culture among the under-25s.

Professor Hobbs said: "The [bouncer's] main task is to regulate their premises and make sure there is good order.

"In many cases we could say that the only force of social order that is prevalent constantly on the street is the bouncers while the police fire from incident to incident.

[Bouncers] are a significant group with regards to social control in this country Professor Dick Hobbs

"The target audience is usually the under-25s and this is the age group that gets involved in most crime and disorder.

"If you ply them with cheap drink then it is not rocket science to suggest you are going to get problems.

"The police have got the same resources they had 10 or 12 years ago to deal with this growing problem and in many ways a market has been created for a new order and that's bouncers.

"They are a significant group with regards to social control in this country."

But Chief Inspector Dave Jackson, of Northumbria Police, said: "The door supervisors work closely with us... but they certainly don't replace us.

"They have good training, hopefully sensible management and sensible licencees behind them.

"They know fine well what the law is because we teach them the law.

"Some of these doormen make very good wages these days and it is not in their interests to be the heavy-handed thugs that people have the perception of from years gone by."

Crime award

Professor Hobbs also added that one-in-five new jobs are created in the night-time industry in what he calls a "major economic shift" of the booming "Alcohol Economy".

He said: "We wanted to understand the way in which this new night-time economy was working, how much money was involved, the way it was replacing traditional manufacturing jobs.

"One of the few ways you can create jobs nowadays is to foster this night-time economy which is based on bars and clubs."

Professor Dick Hobbs' paper - jointly written with postgraduate student Philip Hadfield, Leeds University senior research fellow Stuart Lister and Teesside University lecturer Simon Winlow - was published in British Journal of Criminology.

It also won the prestigious Radzinowicz Memorial Prize, awarded by the national Centre for Crime and Justice Studies.