How do you define"excessive speed" as the cause of an accident. An accident caused by a distraction at 60mph would probably not have occurred if the same distraction had happened when driving at 30mph. But distraction not speed is logged as the cause. These are subjective judgements by policemen who are as falliblein their judgementas anyone else.
BTW the "Association of British Drivers" consists of little more than 2 men and a fax machine with a couple of hundred members total, so their opinions are hardly representative.