2023-2024 ISA Accounts with two different providers

Hi, I opened a 2 year fixed rate cash ISA with Bank A in May 2023 and made a deposit (an amount below the ISA allowance). A few months later, I wanted to switch to a new provider so I opened another fixed rate cash ISA (1 year) with Bank B in Oct 2023 and requested them to arrange the transfer with Bank A. I made a deposit (not much) into the new ISA account while waiting for their response on the transfer because I expected it would be completed shortly. Unfortunately Bank B informed me that the transfer was not successful. At that time I was not aware that I could not subscribe to two cash ISA in the same tax year so I kept both of them. My ISA account with Bank B just matured last month whereas my ISA with Bank A will mature next year. My question is: Do I have to inform HMRC about the interest I have earned from ISA with Bank B when I file my tax return for 2023-2024? Please advise. Thanks.

Hi,
As you could not open two of the same types of ISA at that time, you would need to decide which ISA should be closed. Interest from the ISA that is closed is taxable and should be declared. You should discuss this with your ISA providers. Legislation has changed and you can now open more than one ISA of the same type in the same tax year.
Thank you