Martin Lewis reminds ISAs savers of tax rule that works 'in perpetuity'

Financial expert Martin Lewis has clarified how ISA allowances work for these tax-free savings vehicles. Savers can currently deposit up to £20,000 each year into ISA accounts, with the option to split this amount between cash ISAs and stocks and shares ISAs. A key benefit of ISAs is that any interest you earn or investment returns within these accounts stay entirely tax-free, as long as you don't breach your annual threshold.

A listener reached out to his BBC podcast asking about how the yearly limits function. They presented a hypothetical test case. where a person saves the complete £20,000 in one tax year, then invests another maximum £20,000 on the first day of the following tax year.

The question centred on whether the original £20,000 would become liable for a tax bill, considerin