"also if it is approved by the HSE it is surely adequate" That says all you need to know!

The advantage of a matrix is that these tend to weigh points in relation to the severity (one point for a first aid, three for 7 day reportable, five for a fatality and six for multiple fatalities etc), similarly for frequency. This way, anyone coming new into a job, knows how the originator has come to the conclusion of negligable etc. But a matrix is not necessary, just helpful.

In my view, most matrix-based systems have decided the answer first then fiddled the numbers so they give about the right result, not properly quantified the risk figures to determine what the result really is. I've only ever seen properly calibrated, quantified input data when my work has overlapped with petrochem people. If the inputs are fiddled to give a right-feeling answer, you may as well just skip the numbers stage, because it's all a qualitative exercise anyway and dressing it up as if it were quantitative doesn't actually add any value. I have never not taken action on anything I qualitatively felt was a significant risk just because the numbers said otherwise. Nor have I ever taken action on something the numbers said needed it when I felt it was actually not significant. So why pretend otherwise? It's pseudo-science, and pointless.

Many Thanks for the responses. I think the important thing is that all risks are addressed and that they are in an easily understood format for the required audience. I think that sometimes, as safety professionals, we forget about the audience who have to understand the assessment. My opinion is that the HSE template does that and makes the documents readable. Many Thanks again.