The DWP say that they have begun reassessing every one of the 600,000 claimants who may be eligible for a back-payment of employment and support allowance (ESA).
The underpayments came about because the DWP failed to award income-related ESA to many thousands of claimants who were transferred from incapacity benefit to contribution-based ESA from 2011 onwards.
According to a document released by the DWP, January 2020: ESA underpayments: Forecast numbers affected, forecast expenditure and progress on checking, 600,000 claimants are having their ESA checked for underpayments.
581,000 claimants have now had their assessment completed.
In total £589 million has been paid out so far, with payments averaging £5,000 per claimant.
Around 50,000 claimants were not contacted during the reassessment process because the DWP say it was clear from the paperwork that they were not entitled.
The DWP also say that an undisclosed number of claimants did not respond to multiple attempts to contact them over an eight week period and so their cases were closed.
If those claimants do subsequently get in touch their case will be reopened.
If you believe that you missed out on payment of premiums such as the enhanced disability premium when you were transferred from IB to ESA and you have not been contacted by the DWP you should get advice or contact the DWP directly.