The driver who braked (but was not involved in the accident) is irrelevant.

As FP has said, the usual procedure is that the person at the back of the line, who struck you, and then caused you to strike the vehicle in front of you, is held liable.

However, your case may be complicated by your lack of insurance - for example, the hire company can't hire out their vehicle, so will be coming after you for the money they'd usually be earning.

You may need specialist legal advice. The sort you pay for.

Do you mean no insurance literally - or didn't pay extra for the excess damage waiver?

I mean I added as an extra driver after the fact and was unaware I wasn't taking insurance and didn't notify my insurer to activate my third party on a hire vehicle.

It was done out of ignorance and was a stupid but honest mistake. I know that is a seperate matter if I am found at fault in any way. I will have to pay something. Trust me - beyond being incredibly grateful there were no injuries I was hoping against hopes this is straightforward and the third car's insurance that hit me will pay up...

I offered to pay the damages of the car in front believing her minor damage was less of a hassle than dealing with the inevitable fall out - but she claimed pretty much on the spot and I didn't blame her. If anyone was the least at fault it was her. She managed to avoid the first car.

What I was really trying to get at was if there is established policy in the UK insurance market for collisions of this sort. In America, for instance, the last car in the line is generally always at fault. However given we were all under braking and not stationary they might make the blame 50/50 between the second and third cars as there is no proof of the order of collision.

I am not trying to place blame anywhere. I am just trying to understand how these things are viewed legally. The collision I am referring to...

I will have to deal with the insurance situation when the liability plays out.

How long do these things usually take?