Ed Balls has attacked George Osborne after he appeared to link the case of child killer Mick Philpott with the need to cut benefits, saying the minister's comments were the 'cynical act of a desperate chancellor'.
In a damning indictment of Osborne, Labour's shadow chancellor took to his blog to slam Osborne's "calculated decision to use the shocking and vile crimes of Mick Philpott to advance a political argument."
He said the UK needed to have a proper debate about welfare reform to ensure people cannot "languish on the dole for years and years on end" but accused the chancellor's methods as being "nasty and divisive."
He added: "Our main thought at this time should be about the six children who tragically lost their lives, and the others in the family who have been left to mourn their loss.
"We should have a proper debate about welfare reform.
"And we should discuss what action needs to be taken to tackle the scourge of long-term unemployment including the need for a compulsory jobs guarantee so that people cannot languish on the dole for years and years on end.
"But for the Chancellor to link this wider debate to this shocking crime is nasty and divisive and demeans his office."
It is the first time Balls has waded into the row, apparently having heard the comments after coming back from a 21-mile run. The Labour minister is currently training for a marathon.
However earlier Wansbeck MP Ian Lavery condemned Osborne's comments as "sick, sick, sick." He said on Twitter: "Osborne outrageously using the unspeakable Philpott case in an attempt to boost public support for cutting welfare.
Labour peer Stewart Wood, a close adviser to Ed Miliband, also said: "I can't help but feel it's wrong for Osborne to exploit our horror at the Philpott case to try to boost public support for cutting welfare."
And shadow employment minister Stephen Timms said it was "wrong to link those acts with the debate about welfare" and that George Osborne should not be doing so, even implicitly.
"Millions of people including pensioners and the disabled, people in work and out of work, receive benefits and tax credits. The government needs to recognise that they are as shocked and disgusted by the callous killing of these children as anyone else in Britain," he said.
Philpott, who was jailed for life with a minimum term of 15 years today for killing six of his children, lived in a council house in Derby, claimed thousands of pounds in benefit.
When asked today if the family were a product of Britain's benefit system, Osborne said: "Philpott is responsible for these absolutely horrendous crimes, these are crimes that have shocked the nation. The courts are responsible for sentencing.
"But I think there is a question for government and for society about the welfare state, and the taxpayers who pay for the welfare state, subsidising lifestyles like that. And I think that debate needs to be had."
The chancellor's comments came after the Daily Mail caused controversy after running a story about Philpott with the headline 'Vile Product Of Welfare UK'. Critics accused the paper of manipulating the tragedy to make a cheap point.
Osborne believes the public is on his side in his attempts to cut welfare payments and the issue is expected to be a key dividing line in the 2015 general election.