Iain Duncan Smith has warned that he will demand the prime minister's resignation if Lord Hutton determines that Tony Blair was involved in the naming strategy which led to the unmasking of Dr David Kelly.

In what is being seen as an attempt to up the stakes ahead of the publication of the Hutton report, the Tory leader said Blair should stand ready to consider his position.

"If he did mislead the country, then I absolutely think it will be a resignation issue," Duncan Smith told the BBC's Today programme.

Taking the attack beyond the "sexed up" dossier row, Duncan Smith expressed his horror at the treatment of the late government scientist.

"There is another issue at stake here which I believe is also a resignation issue, and that is the treatment of Dr Kelly.

"If he [Tony Blair] turns out to have been involved and had knowledge of what was going on with Dr Kelly, I think there is no place for him to go but out."

Duncan Smith, who was a staunch supporter of the Iraq war, said he was "absolutely shocked and horrified" about what has emerged over the treatment of Dr Kelly.

"I am appalled that a government can have sunk to this point, where it treats a public servant in this way," he added.

"The key issue here is that the prime minister and his supporters saw his reputation as more important than that of one of his officials, one of the people who is a public servant, and in the course of that we saw the tragedy unfold of Dr Kelly.

"I think the prime minister needs to answer the question whether or not he sees his involvement in that - which at first he denied and has since accepted - as also a resignation issue.

"I certainly do believe it is. If he is involved and if it turns out and is accepted that he knew about that treatment and the way it was happening, then there is no other course but that he should go."

Duncan Smith also told Monday's FT that the government is guilty of too much "total politics".

"My big critique of the government is that they are guilty of this concept of creating total politics in this country. Everything is directed and run in the eyes of the prime minister and this government," he said.

Duncan Smith will face Blair at the despatch box for the post-recess session of prime minister's questions on Wednesday.

The party is also staging an opposition day debate on Tuesday where ministers can expect a fresh assault from their opponents and Labour rebels.