It was deemed to be be 100% my fault. Here, if you run into the back of the car in front, it is always your fault. No exceptions.
It makes sense: you should always leave enough room to stop, so I couldn't really complain. But, if everybody did that on that particular busy roundabout, it would result in gridlock.
I drive for several years, and can say my brain relies heavily on this sort of predictable stuff like "that car has free intersection in front of it, it will move forward".
If you think like a good citizen, yes.
In a country north of UK the law was once the same. People with worn down cars would find the perfect opportunity to slam their brakes, intentionally get hit from behind and claim insurance.