The Highway Code is (as usual) applying its own spin to the actual legislation
Traffic Signs Regulations 2002 says "(e) the amber signal shall, when shown alone, convey the same prohibition as the red signal, except that, as respects any vehicle which is so close to the stop line that it cannot safely be stopped without proceeding beyond the stop line, it shall convey the same indication as the green signal or green arrow signal which was shown immediately before it"
So, "stop unless you cannot stop safely". Nothing in there about causing an accident
Traffic Signs Regulations 2002 says "(e) the amber signal shall, when shown alone, convey the same prohibition as the red signal, except that, as respects any vehicle which is so close to the stop line that it cannot safely be stopped without proceeding beyond the stop line, it shall convey the same indication as the green signal or green arrow signal which was shown immediately before it"
So, "stop unless you cannot stop safely". Nothing in there about causing an accident