John Reid has announced new measures to prevent the employment of illegal immigrants.

The enforcement strategy includes a 'watch list' of illegal immigrants to alert agencies if someone applies for services to which they are not entitled, and workplace enforcement teams to identify employers of illegal immigrants.

There will also be schemes to use immigration data to ensure migrants pay for hospital care.

"Most people who come to this country wish to comply fully with our immigration laws, but where they don't, we are committed to blocking the benefits and privileges that should only be enjoyed by those here legitimately," said the home secretary.

"That's why the time is now right to tackle the root cause of the problem - exploitation."

But shadow home secretary David Davis said the government "is effectively giving up on trying to deport the hundreds of thousands of illegal immigrants in this country".

Other measures announced on Wednesday include the creation of 'immigration crime partnerships' between the Immigration and Nationality Directorate, local authorities, the police, HM Revenue and Customs and local agencies to detect those here illegally and block benefits.

Officials will also begin reviewing how the driver licensing system can be used to identify and combat illegal immigration.

And individuals who overstay their visas could be texted reminders to their mobile phones.

Welfare minister Jim Murphy said his department is "committed to doing all it can to ensure that people who live, work or claim benefits in Britain do so legally".

"We already work in close collaboration with the immigration services and welcome the opportunity to develop even closer links to help put this strategy into effect," he added.

But the Conservatives said the government was simply going to spam illegal immigrants with text messages.

"Yet again we see another pathetic attempt to grab a headline rather than address a problem," added Davis.

"Instead of spin and bluster from ministers, the public deserve effective action.

"Conservatives would establish a dedicated UK border police which would not just secure our borders but also develop expertise in tracking down and removing the huge number of illegal immigrants in this country."