People coming to live and work in Britain should be subject to medical tests, the Conservatives have said.

Last night, the planned HIV tests were criticised as "prejudice-based policy" by Lisa Power, spokesperson for HIV/Aids charity the Terrence Higgins Trust.

"This is not an effective policy and there is no proof that similar measures have worked elsewhere," she said.

Shaun Woodward, the former Tory MP and now Labour member of the Commons human rights committee, said the Conservative move "borders on the obscene".

The Conservatives say the policy is modelled on systems already in use in Canada and New Zealand.

Under the plans, people coming to Britain on a temporary basis for less than six months will not be required to undergo a medical test unless they intend to work in healthcare, childcare or teaching.

But anyone coming to Britain from outside the EU on a temporary basis for over six months but less than a year from a high incidence TB country will be required to undergo a chest X-ray followed up by tests if necessary.

Michael Howard said the British people "deserve the best standards of public health".

Immigration minister Des Browne said the government was already committed to targeted screening for TB.

"The Tory policy is little more than a desperate attempt to catch up with Labour's five year plan," he said.

"It is uncosted, untested and would take Britain back to the chaos that reigned in immigration when Michael Howard was home secretary."

Meanwhile some papers lead on Charles Clarke's claim that Labour wants more, not fewer, economic migrants and refugees.

The home secretary told Labour activists at the party's spring conference at the weekend that London was "utterly dependent" on migration for its economy and the whole country benefits from foreign people coming to Britain to work and study.