Most likely a bad postcode or you simply have not shopped around at ALL?
http://www.carinsuranceexplained.com/car_insurance_explained/insurance_postcode_risk.htm
As others have said using a price comparison site isn't as horrific an idea as many seem to think as long as you
only use it to gauge who's cheap and who isn't. Then phone the cheap people or go direct to their website. I saved circa £100 from going direct.
At your/our/ish age it also may be worth putting your parents and an older sibling on as named drivers. This can actually bring the price DOWN.
Consider a limited milage policy? The big discount seems to start at the sub 5000 miles point.
Also, I assume this is fully comp? I found that TPFT or TP was actually more expensive! I guess they figure that you won't treat your car as well.
On the same note as above, the "market value" of your car seems to make a big difference. Obviously it will cost more to insure a 140k Ferrari but I found I got cheaper quotes for the exact same make/model of car if ther value was 3.5k instead of 3k, nevermind if it was 3.5k instead of 2k.
Try all the above and you'll save yourself a fair whack. When I keep saying "cheaper" I mean £100s not just "a few pound here and there."