"There are many people drinking immediately before approaching the door of venues, either around the corner from the pub, in their cars or in their homes, and it is so difficult for venues to detect that unless someone is very obviously intoxicated when they arrive."

Professor Miller said interviews with more than 4000 patrons revealed those who drank before going out more frequently reported also being involved in alcohol-related violence and harm.

"The relationship was strong,’’ he said.

"We didn’t differentiate between those who initiated the violence and those who were victims of it, but we often found that it took two to tango."

People who drank between one and five standard drinks before going to a venue were 1.5 times as likely to experience harm than those who didn’t drink beforehand, while those who drank six to 10 drinks were twice as likely. For those who drank 25 or more standard drinks prior to going out, their risk increased by 4.5 times.