A former miner who is among those missing out on extra pension payments is calling for the government to address the "injustice".
A pension boost for those signed up to the Mineworkers' Pension Scheme (MPS) was announced in last week's Budget, to address what Energy Secretary Ed Miliband called a "scandal" in historic management of the fund.
Dave Cradduck, who spent 20 years working at Haig Pit in Whitehaven, Cumbria, said it was "unjust" that "not a penny" would be given back to those on a different scheme.
The Department for Energy Security and Net Zero (DESNZ) said the pension funds operated differently and it "must consider the two schemes separately".