Do I need to declare an offshore bank account that earns no interest?

Quick question. I have an offshore back account with a 0% interest rate. All is legit, correct address etc. The money in it was transferred from my savings here.

Do I need to declare this anywhere to revenue?

Just want to make sure I'm keeping within the law.

Thanks!

In any year in which you open an offshore bank account, you need to notify Revenue of the details.
This should be reported on Form 11. If you are a Paye employee, and do not normally make a tax return, the opening of the foreign bank account deems you to be a "chargeable person" required to make a tax return.