Grant
Honorary Master
Driving without due care.
You drive into it from behind, your fault.
that has been covered:
There is no automatic law that says if you drive into the back of someone you are automatically at fault.
Failing to keep a safe following difference is one instance in which you can be negligent, but this doesn't mean you are 100% at fault.
The other car could have had faulty brake lights - then you would have had to apportion fault between the parties.
I always sigh when someone says you are automatically at fault if you drive behind someone.