Santander has a one-year fixed-rate ISA at 4.25 per cent - with tax-free interest fixed until June 2026. ISA stands for Individual Savings Account. The main benefit of an ISA is being able to save without paying income tax or capital gains tax.

The favourable tax treatment of ISAs may change in the future and depends on your individual circumstances. You open the account with £500 or more, Santander says, with a 4.25 per cent one-year fix, 4.15 per cent 18-month fix and 4.10 per cent two-year fix.

All funds mature by 1 June, 2026 with the maturity date set out based on funds deposited by 1 June 2025. If you pay money in before or after this date, you may earn more or less interest than this.

Santander explains: "We work out the interest we’ll pay on your account each day. We’ll pay interest into the account once a year and at the end of the term. It will be available to you the next day."

Somebody depositing a £1k balance will see £42 worth of interest in a one-year fix. The 18 Month Fixed Rate ISA will see £63 worth of interest if £1,000 is deposited, while savers saving into the 2 Year Fixed Rate ISA with a £1,000 bank balance can expect £83.68 back.