Article last updated 20 August 2026.
Cash savings feel safe. But holding more cash than you need – or holding it in the wrong place – can quietly erode your wealth over time. This guide explains how to protect your cash savings in the UK, how much you should keep, and when it makes sense to put your money to work elsewhere.
The two most significant risks of holding too much cash are inflation and tax. Together, they can reduce the real value of your savings even when your balance appears to be growing.
Inflation is the quiet cost of doing nothing. When prices rise, the purchasing power of your money falls. If your savings account pays 4% interest but inflation is running at 3.5%, your real return – the actual gain in buying power – is just 0.5%. If inflation outpaces your interest rate, you’re losing money in real terms every year, even as your balance grows. Imagine a basket of groceries costs £100 today. If prices rise by 5% over the next year, the same basket would cost £105. If your savings earn less than 5% interest, your money may not go as far as it did before.
Over the short term, this effect is modest. Over five, ten, or twenty years, it compounds into something significant.
There’s also an opportunity cost. Long-term investment in a diversified portfolio has historically delivered returns that outpace inflation. Cash held beyond what you genuinely need isn’t just standing still – it’s falling behind. Investing is designed to grow your money over time, but values can rise and fall, particularly over shorter periods, and you may get back less than you invest. Taking a longer-term approach can help smooth these ups and downs, although there is no guarantee that investment returns will exceed inflation.
Interest on cash savings is taxable. The personal savings allowance is currently £1,000 for basic-rate taxpayers and £500 for higher-rate taxpayers. It’s easy to underestimate how quickly interest income can exceed these thresholds, particularly when rates are elevated.
If you hold £100,000 in a savings account earning 4%, you’re generating £4,000 in interest. A basic-rate taxpayer would pay income tax on £3,000 of that; a higher-rate taxpayer on £3,500. The effective return on your cash is lower than the headline rate suggests.
A cash individual savings account (ISA) can help if you’re cautious about risk. Interest earned within a cash ISA is free from income tax, which can meaningfully improve your net return.
From April 2027, the amount you can save in a cash ISA will be reduced to £12,000 for under-65s. If you’re 65 or older, you’ll still be able to save £20,000 in your cash LISA.
However, a cash ISA still carries inflation risk. If you hold cash in an ISA for many years because you’re nervous about investing, you may be protecting yourself from tax while still losing ground in real terms. It can be a sensible short-term shelter, but it isn’t a long-term solution to making your money work.
The Financial Services Compensation Scheme (FSCS) protects deposits of up to £120,000 per person, per authorised bank or building society. For a joint account, that doubles to £240,000. In certain circumstances – such as following a property sale or an inheritance – temporary higher protection of up to £1.4m per person applies for up to six months, provided the relevant conditions are met.
Many people hold significant sums with a single institution without realising that anything above the protected threshold is at risk in the event of a bank failure. This is known as concentration risk.
Spreading cash across multiple FSCS-authorised banks is a straightforward way to reduce concentration risk. It requires a little more administration, but it is a sensible precaution if your total cash holdings are substantial.
It may also be worth considering National Savings & Investments (NS&I). Unlike most savings providers, eligible NS&I products are backed by HM Treasury rather than covered by the Financial Services Compensation Scheme (FSCS). This means there is no upper limit on the protection available. However, interest rates on NS&I products may not always be as competitive as those offered elsewhere, so it's important to consider both the level of protection and the return available when deciding where to hold your savings.
A useful framework is to think about your cash in three layers:
For money you won’t need for five years or more, long-term investment has historically been the most effective way to grow wealth in real terms. But investing isn’t the only alternative to holding cash.
If you have surplus cash but aren’t ready to invest, there are other ways to put it to work:
The point isn’t that cash is bad. Cash is entirely appropriate when it has a purpose. The question is whether all of your cash is doing a job – or whether some of it is simply sitting there out of habit.
If you're not sure whether your cash is in the right place – or whether it could be doing more for you – we're here to help. Our financial planners can review your savings alongside your wider financial picture, so you can feel confident your money is working as hard as it should be.
Speak to a Rathbones financial planner today.
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This material is for information only and does not constitute advice. Tax depends on individual circumstances and legislation and HMRC practice may change. Clients should take personal advice (and tax/legal advice where relevant) before acting. Investments and tax advantaged investments can fall as well as rise and may be illiquid; eligibility and relief depend on meeting conditions.
