The Government may have to pay out hundreds of millions of pounds in unclaimed benefits as a result of the row over scrapping free TV licences for pensioners.
Under the new rule, only over-75s who receive Pension Credit will be eligible for a free licence from next year.
Publicity over the BBC's controversial decision has led to a surge in enquiries from concerned elderly people seeking advice on how to claim the credit so they obtain a free licence.
Charity Age UK has revealed it has been 'inundated' with calls.
The latest Government figures show 650,000 Britons aged 75 and over are eligible for Pension Credit but are not claiming it – about £1.6 billion in 2016-17.
Controversial: The BBC decision to limit the licence fee has proved to be controversial
An increase in Pension Credit claims would also have a knock-on effect for the BBC, as fewer people would be liable to pay for a TV licence.
The Corporation said on Monday that it would strip 3.7 million pensioners of their free licences.
Director-General Tony Hall announced the move, calling it a 'difficult' decision but one that was 'fairest to the poorest'.
Caroline Abrahams, charity director at Age UK, said: 'Ever since the BBC announced its decision to means-test the free TV licence from June 2020, we have been inundated with phone calls, emails and petition sign ups'
Currently, over-75s are exempt from the £154.50-a-year charge – amounting to 4.6 million households. From June next year, the BBC will give free TV licences only to those over-75s who are on Pension Credit – a benefit currently claimed by 900,000 people.
Caroline Abrahams, charity director at Age UK, said: 'Ever since the BBC announced its decision to means-test the free TV licence from June 2020, we have been inundated with phone calls, emails and petition sign ups, to the extent that our IT has sometimes struggled to cope.
'While it's true that every new successful Pension Credit claim will increase the BBC and the Government's bills, we fear hundreds of thousands of older people on low incomes will still miss out.'
Last night, an Age UK petition against the proposal reached half a million signatures.
Consumer campaigner Martin Lewis said: 'Pension Credit is a poorly claimed benefit – let's see this as a clarion call to improve take-up.'
Helen Morrissey, of insurer Royal London, says: 'The coverage of the BBC's decision may well prompt a spike in pension credit enquiries.
Ricky Tomlinson (fourth left) joins protesters outside BBC Media City in Salford, Greater Manchester, at the broadcaster's decision to axe free TV licences for 3.7 million pensioners
'Pension credit is there to help the poorest, and not claiming means they are missing out on valuable top-ups to their income, as well as a host of other benefits, such as discounts on utilities, cold weather payments and free dental care.'
The Department for Work and Pensions used to shoulder the bill for free licences. However, as part of a deal struck in 2015, the then chancellor George Osborne offloaded the responsibility on to the BBC.
The decision to end free television licences for all over-75s will have alerted many to the existence of Pension Credit. But what is it, who’s eligible and how can you claim it?
The benefit, intended as an add to the state pension for those who need it, comes in two parts.
Guarantee Credit tops up weekly income to £167.25 for
