A technician who has "just passed" their apprenticeship will still need significant supervision.

They need to have each task adequately described (or better still over time they relate how they will do it).

They initially need frequent oversight (which can be reduced over time if they are showing suitable work and working practices and conversley increased if work or behaviours are poor).

They should have a wrap up at the end of each task (lessons they have learned and leaving the workplace and tooling clean & tidy).

Over time the supervisor can become more and more hands off but should still interact several time suring the day or shift.

It depends on what the tasks are.  Are they simple and safe, or complicated and with risks?  Have they successfully done these tasks before? How much variation is there in how these tasks can be done and how much does the variation matter (does it depend on picking the right tool for the job, or setting equipment up differently depending on the situation, and what would happen if the wrong choice was made)?  Is there a temptation to take unsafe short cuts (such as picking up something heavy on their own)?  Are there tricks to doing the task correctly that only an experienced operator would know about? What might go wrong that they are not prepared for?  It also depends on the people.  Do they have any individual characteristics that affect how they can do the tasks?  Are they known to be reliable or unreliable?

Depending on all this, adequate supervision might be anything from someone being available to ask for help in case of questions or problems, through a structure of checking in as described by Roundtuit above,  to someone looking over their shoulder.  It's just not possible to give a general rule.  Someone has to make a judgement based on the sorts of questions I've asked here.

By calling them junior technicians you are already stating they are 'inexperienced' and by default need more supervision...there is no legal definition of active supervision (but it is derived from legal principle i.e. the employers duty of care)...and there is a gradation in terms of the type of supervison, as others have alluded to, which is dependant on the task...  Close supervision - Constant normally for high hazard tasks, Remote Supervision - periodic check ins lower risk..not all supervision is constant.

There are a few references to this in CDM, PUWER, Gas Safety and Electricity at Work...

I have introduced in the past a sign off assessment regardless of the qualifications before 'before flying solo'.. which includes stages progression to high risk work..

To determine what constitutes "adequate supervision," it is essential to first understand the reasons supervision is necessary:

1. Required by HSWA S2(2)(d)

Under the Health and Safety at Work etc. Act 1974, employers are required to provide adequate supervision to ensure that:

• Safe systems of work are consistently implemented by all employees.
• Procedures and practices are effectively maintained across the workforce.

This obligation assumes that all employees possess a basic level of competence. Supervision ensures that even competent employees follow prescribed safety systems and uphold standards.

2. Supporting Competence Development

Supervision plays a vital role in developing employees' competence. It acts as a bridge between being "trained" and being fully "competent."

• The amount of supervision required is inversely proportional to the level of competence:
  • Less Competent Employees: Require higher levels of supervision to guide their development and ensure safety.
  • More Competent Employees: Require less intensive supervision but still benefit from oversight to ensure adherence to safety systems.

At no point does supervision become unnecessary. Even highly competent employees still require Type 1 supervision (as described above) to ensure consistent implementation of safe systems of work and to meet legal obligations.

The factors mentioned by others are key in determining what level of supervision would be classified as 'adequate', but difficultly of task and level of risk will form a key part of that decision. 

Hope it helps,

Tony.

Back to basics....any training programme should be based upon the findings of a training needs analysis, this identifies the necessary skills, knowledge and experience required to be a 'competent' person to carry out a given task safely and skilfully. When the trainer/trainers signs an individual off they are stating that the individual is competent to do that task.

A common method of doing this was: do the task while telling me what your doing, now do the task telling me why you are doing that way, and finally do the task while telling me how and why you are doing it that way.

Once you can satisfy your trainer on all three they can deem you competent and therefore carry out that task unsupervised.