David Cameron's efforts to close down speculation over the future of Health Secretary Andrew Lansley have suffered a setback when a senior Liberal Democrat urged his removal.

The Prime Minister used an article to insist he was "at one" with Mr Lansley and backed the controversial NHS reforms going through parliament.

A series of senior Tories were also deployed to television studios in a bid to shore up the Cabinet minister's position.

However, Lib Dem deputy leader Simon Hughes broke ranks to say Mr Lansley should be shifted from his post.

"My political judgment is that in the second half of the parliament it would be better to move on," he said.

A source close to Deputy Prime Minister Nick Clegg stressed that Mr Hughes had been expressing a personal opinion.

Several Conservative Cabinet ministers are said to have privately criticised Mr Lansley's handling of the Health and Social Care Bill, with one suggesting the Government's problems were now on the scale of the Poll Tax in the 1980s.

A Downing Street source was also quoted last week saying that the health secretary should be "taken out and shot".

However, writing in The Sunday Times, Mr Cameron stressed that there was no alternative to reform. The Prime Minister - whose disabled son Ivan died in 2009 - said: "As a parent, night after night, I've known what it is to have the NHS by your side...

"But while the values are right, the system isn't. It needs to change - and that is why I am at one with Andrew Lansley, the reform programme and the legislation going through Parliament."