Deposit Accounts in foreign currency

Probably a silly question for the pinsters but my query is the following…suppose BoI somehow survives this unholy mess and continues to function as a “good” bank. Suppose Germany has enough and decides to pull the plug on the euro and we revert to the old punt. I am assuming all deposits in Euro will be transfered to IRP£ and devalue considerably, but if you had opened an account in GBP or USD and held this currency on deposit with BoI, would they be able to touch this/force you to convert?

Apologies if this has been dealt with in another forum but as you can see from my joined date I am new to this so please forgive the newbie and redirect me to the appropriate thread?

thanks a lot 8DD