Regardless of how fair or unfair this is, it is now standard practice, it was recently covered in auto express, if you claim then your premium will increase even if it was not your fault
they say if you are involved in an accident then the figures show you are more likely to be involved in another !!
its a rip off but they make the rules, i had the same thing recently when an audi tt drove into the back of me !! luckily i wasnt in the zed