'96 renault clit stepson is 18 on a provisional licence, he is a named driver and can earn NCB once he passes his test
TPFT = £385
When he was learning last year, I had my son as a named driver on my policy for a K-reg Peugeot 205. The premiums were about £400.
When he passed his test, the premiums went UP by £120. 
When learning, he had someone riding shotgun and advising on speed, gear, hazzards etc. Once passed test, he is on his own without such advice and thus deemed a substantially higher risk...
What makes you think he took any notice of anything I said?
I just used to cower in the passenger seat and whimper quietly. 
Same thing happened to me, its common sense really, when your a provisonial driver, the "experianced" passenger is responsible for the learners actions. IE he crashes, you get part of the blame.
To be fair, insurance have every right to charge young males fortunes! theres some statistic like 75% of all males between 17-21 have a crash in thier first year, now there car may only be worth buttons, but the merc or bimmer they could hit wont be!
If you want your son to get resonable insurance send him for as many pass plus, advance driving courses etc, as possible, although these might initally cost a fortune, his insurace wont start to be resonable until he's in his 20's so will save a lot of money in the long run and make him a safer driver.
Also a saxo is not a smart car to get a young driver! they are the next generation nova, lots and lots stolen or crashed so a high risk for an insurer to insure.
My first car was a 86 1.3 nissan Cherry at 17 (embaressing yeah but i didnt have £3k to pay to be "cool") which i used for a year, then was put on my mums corsa then at 20 i got my first 106 rallye, a 1.3 that cost £1800 to insure tpft with 3 years clean driving experiance. but it was worth every penny!
