I would think not but I think it's probably best to check with your school/sixth form/college. When I was applying to university, my school insisted (more specifically the sixth form administrator who dealt with UCAS applications) that I declared I was taking STEP that year on my UCAS form despite the fact I didn't want to as I didn't want universities, who didn't normally set STEP offers, to give me one.

I should add good luck for STEP I tomorrow and don't worry about this question for the moment!

Whilst what mr618 said is true, you don't need to declare STEP on your UCAS form if you're planning on sitting it for the first time that year, it doesn't quite handle the case of declaring your already achieved STEP marks on your application if you've already sat STEP. This is a fairly murky topic and half the official sources say you don't have to and the other half say you do. From my understanding (which isn't perfect) you *are* obligated to declare your STEP results and Cambridge will have access to your marks anyway, as they are the ones administering their exams. I understand that Cambridge destroys STEP scripts sometime in October but I think they retain marks and names, so your safest bet would be declaring it. I didn't do great on STEP I when I first sat it a year early and declared it, I still got in anyway.