More than 2,650 people died within six weeks of being found “fit for work”, the Department for Work and Pensions (DWP) has revealed.
Figures released today show that between December 2011 to February 2014, 2,650 people died after being told they should find work following a “Work Capability Assessment”.
Of that figure, 1,360 died after losing an appeal against the decision.
Labour branded the figures a "wake-up call" for the Government, who has faced criticism for the way the assessment tests are carried out.
TUC General Secretary Frances O’Grady called for an urgent enquiry into the figures, and said: “We urgently need an enquiry into the government’s back-to-work regime. These disturbing findings cannot be swept under the carpet.
“The fact that more than 80 people are dying each month shortly after being declared ‘fit for work’ should concern us all. These deaths relate to just one benefit – Employment Support Allowance (ESA).
“We need a welfare system that supports people to find decent jobs not one that causes stress and ill health.”
The figures show that of the 2,650 who died after being told they were "fit for work", 2,380 were in receipt of ESA, while 270 were on either Incapacity Benefit or its replacement, Severe Disablement Allowance.
The DWP were keen to stress throughout its "Mortality Statistics" report that: “Any causal effect between benefits and mortality cannot be assumed from these statistics."
More than 50 charities, acting as the Disability Benefits Consortium Members, called on the Government to reform the way they assess welfare claimants.
Mencap's Rob Holland, co-chair of the consortium, said: “These tragic figures are concerning and warrant further investigation. We know the fit for work test is failing disabled people, with devastating consequences. Wrong decisions can mean people are left with little or no support at all, in some cases struggling to pay for their homes and basic essentials like food and heating.
He added: "These figures should act as a stark warning to the Government to improve the fit for work test and ensure disabled people get the level of support they need.”
Mike Sivier, a campaigner who requested the statistics under Freedom of Information law, welcomed their release and suggested he might now push for details of the causes of death in each case - including cases of suicide.
Labour called the delay in their publication a "disgrace", and Shadow Minister for Work and Pensions Kate Green said: “These figures should be a wake-up call for the Government. Ministers need to focus on sorting out the assessment process so that everyone can have confidence in it, and providing support for disabled people who can work in order to help them do so."
Labour leadership candidate Andy Burnham called for a "national debate" in light of the revelations.
He said: "These are shocking figures that for the first time show the human cost of this Government's punishing benefits regime.
"It raises serious questions about this Government's punitive approach to people on benefits.
"We now need an urgent national debate about these figures, and if elected Leader I would call a full-day debate in Parliament at the first available opportunity.
"This Tory Government has been playing politics with the lives of vulnerable people."
The DWP said the figures showed death rates had remained in line with trends in the wider population for a decade.
A spokesman said: "The mortality rate for people who have died while claiming an out-of-work benefit has fallen over a 10-year period. This is in line with the mortality rate for the general working-age population.
"The Government continues to support millions of people on benefits with an £80 billion working-age welfare safety net in place."
Total number of ESA and IB/SDA benefit claimants who died between December 2011 and February 2014 - 81,140.
Of the 50,580 ESA claimants who died in that time, 7,200 were placed in the "Work Related Activity Group" - the group which the DWP consider are capable of taking immediate steps towards being in work.
Of the 50,580 ESA claimants who died in that time, 2,380 were deemed "fit for work" after an assessment.
Of the 30,560 IB/SDA claimants who died in that time, 270 were deemed "fit for work" after an assessment.
Between 2003 to 2013, the mortality rate of those on out-of-work benefits dropped from 822 per 100,000, to 723 per 100,000.
The general working age mortality rate dropped from 305 per 100,000 to 240 over the same period.
The mortality rate of those on Jobseeker's Allowance is lower than those in work - 218 per 100,000 in 2003 to 138 per 100,000 in 2013
Clarification: An earlier version of this story incorrectly claimed more than 80,000 people died within six weeks of being "flowed off" benefits. This was incorrect and was changed within 15 minutes of the story being published. We apologise for the error. It was further amended when the Department of Work and Pensions confirmed the tables showing those "off flowed" from ESA or IB/SDA with date of death at the same time after appealing a "fit to work" decision was a subset of the table showing the total number of "off flows" after a "fit to work" ruling. The number was 2,650, not 4,140.