Speaking at the 13th National Pubwatch Conference, barrister Gary Grant warned that the Immigration Bill, which he believes is very likely to become law, will have a "direct impact" on licensed premises.
Wrath of the authorities
Grant said police, local authorities and the Government had got "the bit between their teeth when it comes to illegal workers" and that employing them was taken as seriously as distributing class A drugs or guns.
"If last year, the hottest political 'football' was alcohol and what to do about it, the spotlight has now shifted to the biggest bête noire of all – immigration and illegal workers," he said.
"The current offence of employing illegal workers requires knowledge. Knowing about it is very difficult to prove, so what the Government is going to do is replace the existing offence with knowing or having reasonable cause to believe, which is a much lower threshold.
"They are also increasing the prison sentence from two to five years and there will be a sliding scale of punishment if the employer grasses up the worker to the authorities, so there will be a perverse incentive for the employer to grass themselves up as well as the worker."
Changes to the law
He also warned that immigration officers will be given powers to impose illegal working closure notices that prevent premises from opening for between 24 to 48 hours and, in more serious cases, illegal working compliance orders.
Illegal working compliance orders will carry a variety of sanctions, including closure for up to 12 months and regular immigration checks.
Grant added that to avoid the "wrath" of the authorities, licensees should make sure they obtain original documents from workers, make clear copies and take particular care with student visas.
Immigration Minister James Brokenshire has previously said that "rogue employers" face having their businesses closed, having their licences removed or face prosecution.