up to 20,000 died before they received extra cash they were due in their ESA payouts
A Government error has left hundreds of thousands of sick and disabled people owed around £6,000 each in benefits.
The number affected is far higher than originally thought.
But as many as 20,000 people have died during the wait to get the substantial refund.
The Department for Work and Pensions first discovered the issue in 2017, reports the Mirror
The miscalculation dates back to 2011 and it had first been thought around 70,000 people were affected.
The DWP is now looking at 600,000 potential cases – and says it expects around 210,000 people to get a refund because they received too little Employment and Support Allowance.
It has 1,200 staff tasked to solve the problem and says they have so far handed 58,000 people a total of £328 million in back payments.
The total given in these back payments is expected to reach £920 million.
The mistake happened when people were moved from the old incapacity benefit.
At first, ministers estimated up to 70,000 people were affected.
In October 2018 that rose to 180,000 because the DWP agreed to widen the scope of payments. Now it has risen again.
For those claimants who have died, the DWP will have to trace their next of kin to pay back the money.
This will now take until the end of 2019.
A DWP spokesman said: “We are making good progress reviewing and correcting cases and repaying claimants affected by past ESA underpayments, with over £300 million of arrears paid so far.
“All claimants in the first phase have now been contacted and we have 1,200 specialist staff working to ensure no one loses out.
“Where a claimant has sadly died we are ensuring that any arrears owed to them are paid to their next of kin.”
Shadow Minister for Disabled People Marsha De Cordova said: “Once again disabled people are suffering as a result of the chaos at the heart of the DWP.
“This mess is yet another example of the hostile environment created for disabled people by this Conservative Government.