The BBC reports:
The Conservatives have appointed the former Metropolitan Police Commissioner Lord Stevens to lead a working group on creating a border police force.
They would use money saved from scrapping planned identity cards, as well as savings in the Home Office budget, to fund the plans.
Mr Cameron said: “The government’s big idea to try to deal with these problems is ID cards but this demonstrates that their priorities are completely wrong.
“They would waste up to £20 billion without performing one of the most basic tasks of all – securing our borders. In short, ID cards are a bad idea.”
Mr Cameron made his remarks in a visit to a police station in east London.