More than 1,000 pensioners are no longer receiving help to pay their council tax in Calderdale, as charities warn benefit changes are pushing people into poverty.
There were 6,221 pensioners claiming council tax support in Calderdale in the three months to December 2018, official figures show.
This was a drop of 1,132, or 15 per cent, compared to the same period in 2015.
Turn2us, a charity which helps people in financial hardship, said cash-strapped councils were opting to move services online, which is impacting older people.
Campaigns manager Matthew Greer said: "We speak to thousands of people each week through our helpline, many of whom are pensioners, struggling to navigate a complex and increasingly ‘digital-first’ welfare system.
“The fact that so many are now not receiving the correct support for council tax is unfair.
"People who are already struggling to get by end up being sucked further into poverty."
Low-income households in England can apply for a discount on their tax under the Council Tax Reduction Scheme.
The scheme replaced the nationally-administered Council Tax Benefit in 2013, giving individual local authorities the power to decide who is eligible for support and what discounts to offer.
Some pensioners who receive pension credit to top up their income may be fully exempt from council tax.
Others may get a discount if they have less than £16,000 in savings or property, but the amount will vary depending on their income.
The Government says it has protected pensioners, and that they continue to receive the same level of support as under the previous system.
However, there are now 245,000 fewer pensioners claiming support in England compared to three years ago - a drop of 13 per cent.
Out of 326 local authorities, only five did not see a fall in pensioner claimants.
Caroline Abrahams from Age UK said it was important for eligible pensioners to have access to support.
“It is shameful that despite millions of older people struggling financially, at least £3 billion in social security benefits remains unclaimed every year when this extra income could make a huge difference to their lives," she said.
Fewer working-age people are also claiming council tax support in Calderdale, although their numbers have fallen less sharply than in the case of pensioners.
Between October and December, 10,073 working-age people claimed a discount on their tax from the council, down from 11,025 in 2015 – a drop of nine per cent.
The Local Government Association says budget cuts have meant many councils have been forced to reduce the support they give to residents.
Richard Watts, chair of the LGA resource's board, said: "Between 2010 and 2020, councils will have lost almost 60p out of every £1 the Government had provided for services.
“No one wants to ask those on the lowest incomes to pay more but this has put councils in an impossible position."
Local Government Minister Rishi Sunak MP said councils were best placed to make decisions about the appropriate level of support to provide in their area.
He added: "We have given councils access to £46.4 billion this year to allow them to meet the needs of their residents.”