By Ian Dunt
Ed Miliband has raised the stakes in the ongoing row over Ken Clarke's rape policy when he demanded the prime minister sack him by the end of the day.
The comments came after the justice secretary endured a bruising encounter on BBC Radio 5 Live with a rape victim and then made several misjudged comments to Sky News in which he mentioned "serious" rape.
Mr Miliband used his questions at PMQs to ask if Mr Cameron supported Mr Clarke.
"The prime minister, when he leaves this chamber, should look at the comments of the justice secretary," Mr Miliband said.
"Let me say to him very clearly: the justice secretary should not be in his post by the end of the day."
The Ministry of Justice (MoJ) is considering halving the sentence of convicted rapists if they admit their guilt before trial, thereby saving money, increasing the conviction rate and sparing the victim the ordeal of the court case.
But victims' groups say that with many rape convictions carrying a sentence of just five years - only half of which might be served depending on behaviour - some sex offenders could face a sentence as short as 15 months.
The plans are currently only at the consultation phase. Yesterday Mr Clarke said the proposal"is likely to survive" but the strength of the reaction means it is now likely to be dropped.
Mr Miliband told MPs: "The role of the justice secretary is to speak for the nation on matters of justice and crime. This morning the justice secretary was on the radio suggesting that there were 'serious' rapes and other categories of rapes.
"Would the prime minister now like to take this opportunity to distance himself from the justice secretary's comments?"
Mr Cameron said he had not heard the radio interview but added: "Rape is one of the most serious crimes that there is and it should be met with proper punishment.
"The real disgrace in our country is that only 6% of rapes that are reported to a police station end in a conviction."
In the aftermath of the session, No 10 offered an unmistakeable message to Mr Clarke.
"I would hope the justice secretary would want to make clear how seriously he takes all kinds of rape," the prime minister's spokesman said.
Mr Clarke has since said he had made a "mistake" in his choice of words although he refused to apologise.
"If people have been offended by those comments then clearly that's regrettable," he said.
The rape victim told Mr Clarke on BBC Radio 5 Live: "He [the offender] served just over a year and a half, he was released on licence and... he further reoffended and he further reoffended."
Mr Clarke admitted he had not spoken to any victims about the plans.
"I haven't put this idea to women who've been raped because I haven't met one recently but my experience of rape trials is that contesting a rape case makes things worse [for the victim]," he said.
The justice secretary was then forced to appear on Sky News, as the media outrage over the plans grew.
"The main aim of my reforms is to cut re-offending," he said.
"I'm not actually reducing the tariff of any crime. This is all nonsense."