I think it'd be really risky; and if you got rejected, it will have been a complete waste of a year.
BUT... Having said that... If you feel really confident, I'd recommend it. But I mean REALLY confident. If you got 3 A*'s at A-Level, I'd definitely do it. But I think it's worth knowing that some may argue that you haven't exactly taken the 'hardest' subjects. I think for Psychology they also like to see Maths A-Level, but I could be wrong.