The former chief inspector of borders and immigration has said the UK is still failing to get “the basics right” on the issue.
John Vine told Radio 4’s PM that existing rules and regulations need to be enforced in order to achieve “much more toughness in some areas”.
He also questioned the government’s aim of reducing net migration when some of the factors were out of its control.
The Home Office said it was restoring order to the immigration system.
Speaking publicly for the first time since leaving his post, Mr Vine said: “There is still much more room for improvement in getting the basics right; ensuring that staff know their powers under the law.
“There is also tremendous room for improvement in terms of enforcing rules and regulations that exist in order to make sure that there’s much more toughness in some areas of immigration.”
‘Not in control’
Mr Vine, who left his job at the end of 2014, also said it would be “very difficult” to implement a net migration cap, as the government hopes to do.
“It’s very difficult to implement something when you are not in control of all the factors,” he said.
“And I think that has been the challenge with the net immigration target – that there are factors in it outwith the control of anybody, really.”
John Vine, left, said the debate was still like a discussion in a pub
He called for more information on immigration to be put in the public domain.
“I think sometimes the debate on immigration seems to have not progressed from two guys sharing a pint at the bar of a local pub,” he said.
He added: “There needs to be far more information put into the public domain to inform the debate.”
Mr Vine also said there had been “some improvement in some areas”, including more consistency with border checks.
A Home Office spokesperson said: “The British public wants to see immigration reduced and controlled.
“That’s why this government is restoring order, clamping down on abuse, and building an immigration system which works in the national interest.
“Our reforms have cut net migration from outside the EU by nearly a quarter since 2010 – close to levels not seen since the late 1990s.”
The spokesperson said Mr Vine’s work had been “invaluable”.