Police have been granted tough new powers to arrest licensees of premises where customers are found to be taking or dealing in illegal drugs.
This change to the Misuse of Drugs Act will mean that police will be able to arrest licensees if drugs such as ecstasy and cocaine are found.
But publicans in some of the UK's larger cities could face a tougher time than others.
John Henley, licensee of Bar Fringe in Manchester city centre, said he would welcome the move if it "weeded out the few less professional licensees who turn a blind eye to drugs".
But he said he was concerned that the police could take on an extreme role rather than working with the local community to tackle the problem.
Dave Wickett, licensee of the Fat Cat in Sheffield, branded the new laws as "unfair".
"I can understand it if publicans are deliberately flouting the law and allowing customers to use drugs, but in many cases we do our best to make sure drugs are not part of the culture," he said.
"To say that we could get into trouble when we are already doing our best to keep drugs out, is really tough."
But Bob Cartwright, communications director for Bass Leisure Retail, said the company was confident that the changes to the Misuse of Drugs Act 1971 would not cause much of a problem.
"Managers, barstaff and doormen are all trained to be constantly vigilant," Mr Cartwright said.