DAVID Cameron's crackdown on immigration has come under intense fire, with critics questioning whether it can be implemented.

Ed Miliband, the Labour leader, warned the Prime Minister not to try to "out-Farage Farage", a reference to the leader of Ukip, which campaigns against "open door" immigration from Europe.

Mr Cameron described the Coalition's Immigration Bill as the "centrepiece" of its new legislative programme, which will make it easier to remove people from the UK by limiting rights to appeal and tightening the use of human rights law.

Under the proposals, businesses, landlords and doctors will all be asked to check the immigration status of foreign workers, tenants and patients, or face hefty fines.

On healthcare, the UK Government intends to ensure temporary migrants make a contribution to NHS care they receive. However, Clare Gerada, chairwoman of the Royal College of General Practitioners, warned: "GPs must not be a new 'border agency' in policing access to the NHS."

She said while health tourism must be brought to an end, it was important not to overestimate the problem.

"GPs have a duty of care to all people seeking healthcare and should not be expected to police access to healthcare and turn people away when they are at their most vulnerable," she added.

A Scottish Government spokeswoman stressed NHS boards in Scotland already had the ability to recover costs from migrants and that the Scottish private rented sector was "already subject to a range of regulatory measures aimed at promoting quality, growth and tenant welfare".

However, she added that thus far the UK Government had not provided Edinburgh with any details of the Bill.

Michael Clancy, from the Law Society of Scotland, noted that the Coalition's proposals for private landlords were "likely to have a significant impact on private sector tenancies in Scotland".

He added: "As housing is devolved to the Scottish Parliament, it will be interesting to see how this measure would be implemented in Scotland."

In his Commons address, Mr Cameron insisted the Coalition was on the side of those who worked and saved hard, which meant reform was needed in the immigration system "so we attract people who will benefit this country".