I am trying to locate some kind of official guidance (e.g. HSE/HSENI) on what a Safe system of work should contain so I can draw up a template proforma. I have found lots of examples of other organisations and what they have produced but unfortunately I have not been able to find an offical clear guide. I am probably missing something really obvious but would appreciate any assistance anyone can provide.

Unless Guru or others know difefrently I don't think that you are likely to find any 'official' guide. The principles book does have a section on ssow, but to my mind, depending on the circumstances, they can be very short and simple, such as a bulleted list, or long and complex. I do not believe that there is a 'one size fits all'. In it's simplest form it is merely an instruction from managers to workers on how to do a job safely. It should have within it an instruction to stop work if they are unsure of anything or they come across a situation that the ssow does not cover.

I would agree with previous comments that it would be hard to imagine a "one size fits all" approach regarding SSW. It would be worth considering though that a SSW surely could only be developed after carring out a full risk assessment so it can'r really be a generic issue.

Sorry, the 'principles' book to which I referred is the IOSH 'Bible, called something along the lines of the Principles of health and safety at work - it ia available through IOSH or Amazon as well - a good quick refrence book