Throughout the world, women involved in criminal justice systems often present with substantial needs and vulnerabilities. Diverting vulnerable people away from prison is government policy in England and Wales, but full psychiatric and social assessments are expensive and hard to access. A screening and quick response initiative ‐ alternatives to custodial remand for women (ACRW) ‐ was implemented across three areas of London (West, South and East) to supplement existing court liaison and diversion services, to assess the feasibility of a supplementary custodial remand service as part of a women’s specialist service pathway in the criminal justice system in England. Three mental health trusts and two voluntary sector providers offered this service enhancement – a screening and service link provision in three London boroughs between 2012 and 2014. We conducted a service evaluation using routinely collected service use record data. The service made 809 contacts, of whom 104 had contact on multiple occasions. Many were identified as at risk of self‐harm (46%) or had histories of hospital admission for mental disorder (36%), but few were referred either to the liaison and diversion service or specialist mental health services. The largest group of referrals was to women’s community services outside the health service (e.g. counselling, domestic violence or sexual abuse services). 180 women had dependent children and 22 were pregnant, increasing the urgency to find non‐custodial alternatives. As well as confirming high levels of need amongst women entering the criminal justice system, this evaluation confirms the feasibility of working across sectors in this field, providing an extra layer of service that can complement existing liaison and diversion service provision. The service was responsive and most women using it were kept out of custody. Research is now required to understand the appropriateness of the referrals, the extent to which women follow them through and the impact on their mental health and desistance from offending.