Circumstances surrounding emergency detention under the Mental Health (Scotland) Act were examined, with particular regard to whether consent was obtained from a third party. Twenty-eight ot 100 consecutive detentions occurred without consent. These patients were more likely to exhibit aggressive behaviour and be detained by a psychiatric registrar or senior registrar. Mental disorder was doubted more often and detention was less often continued. Reasons given for failing to obtain consent were frequently inadequate and possible explanations are discussed. Increased education and supervision of trainees resulted in a substantial fall in cases of non-consent in a follow-up sample.