Declined my university offer and now regret it, can I apply through clearing?

I made a late application for a university course for this September, and received a conditional offer (subject to an interview). However, I decided to decline the offer yesterday and withdraw from my other choices with the aim of going to university next year instead.

However, I'm not regretting that decision. The course still has places in clearing, can I reapply via clearing or will it be frowned upon?

I want to go this year instead. I'm going to ring UCAS first thing tomorrow