Pensioners pleased to see they will now qualify for the Winter Fuel Payment this year may want to check up on a HMRC rule that could mean they still miss out. Labour has opened up the eligibility, so now most people of state pension age will qualify for the payment, which was worth £200 or £300 last year. However, you will have to pay back the amount if your income is above £35,000 a year. When working out your total income, there is one factor you may overlook as it's not a direct source of income - the interest earnings on your savings.

Jeremy Cox, head of Strategy at Coventry Building Society, warned: "Thousands could still unknowingly be left out in the cold - not because they're earning more, but because their savings are. Many pensioners may not realise that interest earned on savings held outside of ISAs count towards their total taxable income.

"With still relatively high, even modest savings can generate income that pushes someone over the threshold."

To explain how your savings growth could tip you over the threshold, Mr Cox gave the example of a person with £20,000 in a savings account earning 4.5.%.

This person would be earning £900 in interest each year and this amount would fall in the category of taxable income and count towards the £35,000 limit for the Winter Fuel Payment.

You may not realise your interest earnings fall into this category as if you are on the basic rate for income tax, you can earn up to £1,000 a year in interest tax free. Yet the amount is still classed as taxable income.

Given this little-known rule, savers may want to move over their funds into an ISA, where all of your interest earnings or investment growth within the account are entirely tax-free, and so would not count towards the £35,000 limit.

Mr Cox explained: "ISAs offer a tax-free way to keep savings interest out of the income equation. Interest earned within an ISA is never taxed and does not count toward income calculations.

"With the £20,000 cash allowance still available this tax year - and potential changes looming - they remain a smart choice for pensioners looking to protect their eligibility for benefits like the Winter Fuel Payment."

You can deposit up to £20,000 a year into ISAs, and this can be divided between different types of ISA, including cash ISAs, stocks and shares ISAs and innovative finance ISAs.

Now is also a good time to max out your ISA allowances as there have been suggestions that Labour could bring in an additional £4,000 cap on how much you can put into cash ISAs, to try and encourage people to use stocks and shares ISAs more.

With the new rules announced for the Winter Fuel Payment, people have been urged to be vigilant as scammers will likely seek to take advantage of the update, and try to lure people in with fake messages purportedly from the Government.

Siobhan Blagbrough, financial crime manager at , said: "We're already seeing fake messages pretending to be from the Department for Work and Pensions (), urging pensioners to 'apply now' or risk missing out on their £300 payment.

"These scam texts often include fake links and ask for personal details or for people to reply 'YES' to claim the payment. These messages are bogus.

"The has confirmed that eligible households will receive the money automatically, and no application is needed." If you have clicked ona fake link or handed over your details, you are encouraged to contact your bank immediately to report the matter.

You can also report it to Action Fraud by caling 0300 123 2040.