How do i get really cheap car insurance for a 20 year old?

My son is 20 and hes just bought a Peugeot 106 and is getting quotes at £2300, I think this is ridiculous. I have tried getting it in my name and putting him down as 2nd driver but it goes up to around the same price once I add him. Surely there must be some cheap insurance out there somewhere for him. All he does is go to work and drop his girlfriend off, the car is only a 1.1 so is not powerful and ive seen him drive, he is sensible. Hope somebody can help.