In March 2020, the Royal College of Physicians in the UK published national guidelines on the management of patients with prolonged disorders of consciousness, updating their 2013 guidance 'particularly in relation to recent developments in assessment and management and … changes in the law governing … the withdrawal of clinically assisted nutrition and hydration'. The report's primary focus is on patients who could live for many years with treatment and care. This update, by a neurologist, an imaging neuroscientist, and a lawyer-ethicist, questions the document's rejection of any significant role for neuroimaging techniques including functional MRI and/or bedside EEG to detect covert consciousness in such patients. We find the reasons for this rejection unconvincing, given (i) the significant advances made in the use of this technology in recent years; and (ii) the wider scope for its use envisaged by the earlier (2018) guidelines issued by the American Academy of Neurology. We suggest that, since around one in five patients diagnosed with prolonged disorders of consciousness are in fact conscious enough to follow commands in a neuroimaging context (i.e. those who are 'covertly conscious' or those with 'cognitive motor dissociation'), and given the clinical, ethical and legal importance of determining whether patients with prolonged disorders of consciousness are legally competent or at least able to express their views and feelings, the guidance from the Royal College of Physicians requires urgent review.