Paying off a 0% card question

Southpaw

Hi

I have an M&S card which has a 0% until October 2007 which has a £5k limit.

My question is At the moment I have about £3.5k on it. If I was to pay that off in full then continued to use my card and for example spent £500 on it and didn't pay that off before the 0% ended what would I pay 15.9% on?

Would it be only on the £500 or would interest be calculated on the whole £4k?

Or would this only apply if I was to pay off £3k and left £500 on the card?

Thanks in advance.

Phantom_Flan_Flinger

The interest will be calculated on the outstanding balance at the point where the 0% ends.