is Gov Stamp Duty only payable if card has been activated?

Tedious Bore wrote: »

So... if I've had a credit card posted out to me ages ago but never activated it via ATM as per instructions that came with (because I've just been using my debit card the whole time instead), will there still be an automated €30 stamp duty fee taken from my current account for the credit card I never used?

Technically, the stamp duty is charged on the credit card account, rather than on the physical card itself.  So once you create the account the liability arises, regardless of whether the associated card is ever used or activated (or, in theory, issued).  

Howevver, if you open a credit card account and then close it in the same tax year, without ever having used it (i.e. there are no transactions on the account when you close it, other than an account maintenance fee) then the stamp duty is not collected.