Posted By Andrew Gordon Intersting one Keith,I manage all the contractors that work for our company and we have different kinds of contracts they need to sign before work commences, at present we have nothing in place to ensure that a contractor would be "fit for work" I would think it would be very difficult to implement a system to cover this, the only thing would be to get them to sign some sort of disclaimer linked to the type of work they are doing.

Posted By Kieran J Duignan Keith As a self-employed chartered psychologist (and registered safety practitioner), I have been very aware of this question for some time because one of the working principles of counselling is that a counsellor should not work with a client if he or she is too stressed to do it effectively. If the client were to complain formally, I would risk a formal reprimand or worse if it were determined that 'fatigue' or 'stress' contributed to failure or negligence on my part. At the same time, when I have occasionally worked in an industry (e.g. animal laboratory in the pharmaceutical industry) presenting high physical and security hazards, I have noticed the care with which the employer took to provide personal protective clothing and to require me to sign very detailed agreements. While, as Fats observes, disclaimers may not avoid all ambiguity, well-drafted ones appear to fulfil the condition of the 'reasonably practicable' responsibility of an employer and main contractor.