Background Despite improved mental health services in prisons in England and Wales, there are often delays in transferring acutely mentally ill prisoners to hospital, particularly in the London area. Aim To establish whether clinical pathway interventions can reduce such transfer delays. Methods Two clinical pathway interventions – one based in a medium secure forensic hospital and the other in a remand prison (pre‐trial/sentence) – were independently introduced to manage referrals of prisoners with acute mental illness in London, UK. Time taken to transfer to hospital was measured for each and compared with the best available estimates for time to transfer prior to the new pathways. Results Both interventions produced significant reductions in prison to hospital transfer times. Conclusions/implications for practise The nature of the projects precluded ideal research design, but despite small sample sizes, provision of modestly funded small but dedicated elements of service to target the specified problem of transfer to hospital delays showed a significant advantage for such provision, whether hospital or prison based, psychiatrist or nurse led. Further research is now required to examine the whole pathway. More secure psychiatric beds may be required, at least in the short term, to support diversion policies and enable compliance with national policy directive, and to establish whether redesigned pathways can enhance treatment and behavioural outcomes for acutely mentally ill prisoners on a larger scale. Copyright © 2013 John Wiley & Sons, Ltd.