The Conservatives have called for the government to create an independent public health commissioner.

Shadow health secretary Dr Liam Fox said the post was needed to issue frank advice on issues such as Aids and obesity which need to be higher up the political agenda.

The party will today publish measures aimed at stopping Britain being seen as a "soft touch" for free health care by immigrants and visitors from overseas.

Under the plans, all immigrants and asylum seekers would have to undergo screening for infectious disease and would be barred if considered a possible burden on the NHS.

"The Blair government has stood silently on the politically correct sidelines while Britain has experienced a second Aids wave, largely imported from Africa, an explosion of sexually transmitted disease among our young people, and a tidal wave of obesity that threatens to create a secondary diabetes epidemic that could swamp the NHS in future," Dr Fox said.