The use of prisoners as research participants is controversial. Efforts to protect them in response to past exploitation and abuse have led to strict regulations and reluctance to involve them as participants. Hence, prisoners are routinely denied the opportunity to participate in research. In the absence of comprehensive information regarding prisoners’ current involvement in research, we examined UK prisoners’ involvement through review of research applications to the UK National Research Ethics Service. We found that prisoners have extremely limited access to research participation. This analysis was augmented by a survey of those involved in research and research governance (UK researchers and Research Ethics Committee members). Our results suggest that pragmatic concerns regarding the perceived burden of including prisoners are far more prominent in motivating their exclusion than ethical concerns or knowledge of regulations. While prisoners may remain a vulnerable research population due to constraints upon their liberty and autonomy and the coercive nature of the prison environment, routine exclusion from participation may be disadvantageous. Rigorous ethical oversight and the shift in the prevailing attitude towards the risks and benefits of participation suggest that it may be time for research to be more accessible to prisoners in line with the principle of equivalence in prison healthcare. We suggest the necessary first step in this process is a re-examination of current guidance in the UK and other countries with exclusions.