Martin Lewis warns thousands are missing out on free cash – how to claim £400 help now before you lose it

He said: "Those on prepayment [meters], you'll get vouchers, they'll email you, they'll post it or they may text you about it so watch out for that.

"So many people haven't redeemed their vouchers."

He said that 20% of eligible people, often vulnerable, have not redeemed their vouchers from October and November.

The help is being paid out over a six-month period, which started in October and will end in March.

Customers received a £66 discount in October and November, and then £67 in December through to March.

The discount is automatically taken off your bill, unless you’re on a traditional prepayment meter, where you’ll be sent vouchers via text, email or post to redeem.

As vouchers expire after 90 days, it means that the deadline for claiming these was Saturday, January 14 - which has now passed.

Meanwhile a new scheme has launched offering those off the gas grid £200 help.

Martin warned that households off-grid and on prepayment meters will begin to get their £200 cost of living vouchers any time now.

The support is part of The Alternative Fuel Payment (AFP) scheme and helps struggling households knock money off their energy bills.

But the MoneySavingExpert.com (MSE) founder warned that thousands of households are at risk of missing out because they haven't redeemed them.

Martin said the payments should all be made by the end of this month.

Roughly 2.5million households who live off the gas grid have been able to apply for the funds from the start of this week.

Brits will only get the cash if they warm their home using alternative energy sources such as heating oil, biomass and liquefied petroleum gas (LPG).

To be off the gas grid means you don't use mains gas. That means you'll only get the cash if you warm your home using alternative energy sources such as heating oil, biomass and liquefied petroleum gas (LPG).

Recent government data suggests that Northern Irish households rely on heating oil the most - and costs have risen by up to 120% in recent months.

How can I get my voucher if I missed the deadline?

Don't panic - missing the deadline doesn't mean that you've lost your £66 forever.

Even if the deadline passes, you can still get your voucher for October re-sent to you if you didn't claim, or receive, it.

You need to call your energy supplier to ask for a new one.

But you should claim your voucher sooner rather than later to avoid the admin stress - and to get the vital help quicker.

Make sure all your personal details are up-to-date.

Your voucher may have been sent to the wrong email address or phone number, for example.

More energy support

If you're not eligible for the £200 or £150 for business, there's more you can receive.

Millions on benefits are in line for up to £1,350 in free cash from spring.

The help is aimed to help soften the blow of high energy bills, food costs and other necessities.

The first chunk of the  will be paid directly into claimants' accounts.

Unlike last year's help, this cost of living payment will be paid in three, not two, instalments.

More than eight million people will get the help directly to their bank accounts, and the £900 help will be paid over the financial year.

And don't forget to keep checking your local council for the Household Support Fund scheme.

Do you have a money problem that needs sorting? Get in touch by emailing money-sm@news.co.uk