Hi Jayne

Generally, there is no such requirement for teacher / instructor / trainer qualifications - which are usually anyhow only a guide to anyone's real competence as a trainer - there are plenty of ace trainers and academics who haven't any  formal teaching qualification to their names and that doesn't make them any less competent or effective.

However, there are specific circumstances when there is, such as OFSTED now requires work based learning trainers to have specified teaching etc qualifications and Dept for Education do the same for certain school teachers.

Most qualification awarding bodies require evidence of occupational competence of anyone involved in assessing and signing-off learner competence but not usually of tutors as such.

But this is necessarily very generally - you'll need to be more specific about the particular circumstances to be sure.

If it is a certificated course awarded by C&G or similiar - or NEBOSH then I'd simply phone them up and ask someone there. Acreditation sometimes varies. 1st Aid certs awarded by some providers insist that the person must be instructed/trained and certified by themselves before they are let loose and awarding certificates to other people.

However it depends on what you mean by 'valid'. In the case of machine operators, are you trying to meet some legislative requirement? - As in "all machinists should undertake suitable and sufficient training......." then I'd say that as long as a competent person was doing the training their training skills won't normally be questioned.