Paint peeling, how did it happen, how can I fix it?

My 2009 Fiat Punto's paint has started peeling in places. It's the top layer, the one that makes it shiny that has gone. I've attached a picture. The car is street parked (in the UK) so is out in all weathers but obviously not extremes (This is the UK!)

How might this have been caused and can I repair it or is it a complete re-spray job?

Any ideas, experience or information would be great.

Attached Images

23-08-28 bonnet.jpg (263.3 KB)