During my working years and numerous contacts with insurance companies, it was pointed out to me, quite abruptly at times, that it is a No CLAIM Bonus not a No BLAME Bonus.
So, as wrong as it may be, if you make a claim, they will pay out and if they can recoup all their losses from someone else, it shouldn't affect your following years premium. You will find that you have to declare it when asked the question about any accident or claims in the last 3 or 5 years.
Technically, even if you don't go through the insurance, the question they ask is accidents or claims, so you should tell them regardless.
I had more than a couple of "Tactical Contacts" through work and sometimes while renewing my personal car insurance, they would ask about work accidents.
I once dealt with a kid who crashed his car, he'd paid a fortune as a young lad for fully comp. He made a mistake and totalled it. The insurance refused to pay out because he hadn't declared his alloy wheels were non standard. Wheels that were a dealer option when new and were on the car when he bought it as the 3rd owner!
As someone has already said, car insurance is virtually legalised robbery, you have to have it, but they pretty much set their own rules and you will never beat them.