The most recognised qualifications are the NEBOSH Certificates and Diplomas, have a look at their websites. These courses will enable you to become a member of IOSH. The General and Construction Certs are Level 3 the Diploma is Level 6 if memory serves me right. Instead of the Nebosh Diploma you could always complete the NVQ Level 5 Diploma in Occupational Health and Safety. Again have a search on google for courses. Hope this helps, any questions feel free to give me a shout.

Apologies misread, been a long day and only 11am!! Would say perhaps capable of acquiring and retaining detailed legal, technical and commercial information, communication. From experience the competencies I have gained like hazard identification and assessing risk come from completing the courses as well as on the job training or working in the environment. I started in the construction industry with little knowledge or either H&S or construction but was completing a course at the time, i found that working in environment and studying helped me to develop competencies etc.

HSE will usually look for graduate qualifications as well as H&S. They have a rigorous programme of mentoring and additional training etc. before Inspectors are let loose, which varies according to the specialist area. No doubt and Inspector or ex-Inspector will be along here shortly to flesh out a reply.

If it is any help at all I'm pretty sure they follow the Civil Service behavioural competency dictionary. Used to have one but....