Martin Lewis has given a stern warning to savings account holders hoping to make some cash with their extra funds.

During an appearance on ITV's This Morning, the money expert told viewers "there is no loyalty in financial services" and said everyone should switch accounts to get a better rate.

He also recommended viewers transfer their savings to a different account - and it's not to your usual bank or building society.

Instead he has advised savvy bankers to put their savings into a Treasury backed National Savings and Investments account.

It comes as savings rates have hit rock bottom, with more than 370 accounts disappearing from the market since March, Moneyfacts figures show.

While official figures suggest a spike in people saving over lockdown, the vast majority are earning almost nothing on their cash.

Hundreds of top-paying accounts have disappeared since March

According to the Bank of England, savings deposits increased by £14.3billion in March, followed by a record £25.6billion in May.

But two consecutive cuts to the base rate, as well as other measures to stimulate the economy, have reduced rates to zero.

"Savers will be in for a shock to find the first six months of 2020 have been the worst for rate cuts in over a decade," said Rachel Springall, of Moneyfacts.

"This demonstrates how much the market has been impacted by the coronavirus pandemic and base rate cuts, and it will leave savers feeling frustrated and disappointed."

So where should you put your cash?

This is the question consumer champion Martin Lewis sought to address on This Morning, after one viewer named Kitty got in touch about her savings account.

"My bank has just been in touch to explain it's reducing the interest on my savings account from 0.25% to 0.01%? Should I still keep my money in a savings account or should I move it elsewhere to get a better rate," she asked.

"Yes, move your money elsewhere to get a better rate," Martin responded.

"Loyalty does not pay in financial services. It's important to always monitor the best rate.

"Savings rates were bad before and now they are even worse."

The consumer expert said the top-paying easy access savings account right now is through NS&I, stating "it's as good as you're going to get".

NS&I accounts - all you need to know

The account currently pays up to 1.16% on savings

NS&I (National Savings and Investments), which provides products such as Premium Bonds, is backed by the Treasury.

In February, the lender announced a raft of savings rates cuts, including making the Premium Bonds prize fund rate less generous, however it later U-tuned on the decision due to the coronavirus pandemic.

It currently offers the top account at 1.16% via its Income Bonds – though you'll need to deposit at least £500 to access it.

These restrictions won't be an issue for some, but if you're looking for an account you can dip in and out of, NS&I's Direct Saver may be a better option. It pays a bit less at 1%, but you can open it with just £1 and it gives full flexibility on withdrawals.

Whichever account you pick, it's worth checking your rate regularly to make sure you're getting the best possible returns.

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The good news is that the account is expected to stay for the long-term.

Sarah Coles, personal finance analyst at Hargreaves Lansdown, said: "Savers will be breathing a huge sigh of relief at the news that NS&I is going to be there for them through the crisis.

"NS&I has been single-handedly holding up rates in the easy access savings market. Its income bonds have topped the charts, offering 1.16% - which is far and away the best rate on the market. Other banks will compete for short periods at a time, but nobody else has the capacity to soak up the huge sums of money we put away during lockdown.

"The worry was that NS&I might be forced to cut savings rates, and that other competitive rates on the market would follow suit.

"These competitive rates have attracted a huge amount of cash. Overall, NS&I increased the cash it held by £14.5 billion in the first three months of the year.

"Given that it was only aiming to raise a maximum of £9 billion during the entire year the... worry was that it would attract too much cash, and be forced to slash rates."