We can sometimes backdate the start of your Housing Benefit and Council Tax Support for up to three months before the date you claimed.
You do not need to tell us why you didn't claim sooner as we should look out for claims we can backdate.
'Reducing the amount of backdated pension credit, housing benefit and council tax benefit older people can receive to just three months will penalise some of the poorest pensioners.'Lib Dem MP Lynne Featherstone, who uncovered the figures, described the plans as 'the worst kind of Labour penny-pinching'.
She said: 'The Treasury is in for a real windfall at the expense of some of the poorest people in the country.'Pensioners on fixed incomes are bearing the brunt of bumper rises in fuel and shopping bills.
Proposals to change the backdating of pension credit will save £100million next year and £96million in 2010.