15 A prisoner against whom any means of force have been used should have the right to be immediately examined and, if necessary, treated by a medical doctor. This examination should be conducted out of the hearing and preferably out of the sight of non-medical staff, and the results of the examination (including any relevant statements by the prisoner and the doctor's conclusions) should be formally recorded and made available to the prisoner. In those rare cases when resort to instruments of physical restraint is required, the prisoner concerned should be kept under constant and adequate supervision. Further, instruments of restraint should be removed at the earliest possible opportunity; they should never be applied, or their application prolonged, as a punishment. Finally, a record should be kept of every instance of the use of force against prisoners. 54. Effective grievance and inspection procedures are fundamental safeguards against ill-treatment in prisons. Prisoners should have avenues of complaint open to them both within and outside the context of the prison system, including the possibility to have confidential access to an appropriate authority. The CPT attaches particular importance to regular visits to each prison establishment by an independent body (eg. a Board of visitors or supervisory judge) possessing powers to hear (and if necessary take action upon) complaints from prisoners and to inspect the establishment's premises. Such bodies can inter alia play an important role in bridging differences that arise between prison management and a given prisoner or prisoners in general. 55. It is also in the interests of both prisoners and prison staff that clear disciplinary procedures be both formally established and applied in practice; any grey zones in this area involve the risk of seeing unofficial (and uncontrolled) systems developing. Disciplinary procedures should provide prisoners with a right to be heard on the subject of the offences it is alleged they have committed, and to appeal to a higher authority against any sanctions imposed. Other procedures often exist, alongside the formal disciplinary procedure, under which a prisoner may be involuntarily separated from other inmates for discipline-related/security reasons (eg. in the interests of "good order" within an establishment). These procedures should also be accompanied by effective safeguards. The prisoner should be informed of the reasons for the measure taken against him, unless security requirements dictate otherwise, be given an opportunity to present his views on the matter, and be able to contest the measure before an appropriate authority. 56. The CPT pays particular attention to prisoners held, for whatever reason (for disciplinary purposes; as a result of their "dangerousness" or their "troublesome" behaviour; in the interests of a criminal investigation; at their own request), under conditions akin to solitary confinement. The principle of proportionality requires that a balance be struck between the requirements of the case and the application of a solitary confinement-type regime, which is a step that can have very harmful consequences for the person concerned. Solitary confinement can, in certain circumstances, amount to inhuman and degrading treatment; in any event, all forms of solitary confinement should be as short as possible.