Abstract Background In recent years the UK has expanded the provision of liaison mental health services (LMHS). Little work has been undertaken to explore first-hand experiences of them. Aims The aim of this study was to gain insights into the experiences of users of LMHS in both emergency departments and acute inpatient wards in the UK. Methods This cross-sectional internet survey was initially advertised from May-July 2017 using the social media platform Facebook. Due to a paucity of male respondents, it was re-run from November 2017-February 2018, specifically targeting male respondents. The survey featured a structured questionnaire divided into three categories: the profile of the respondent, perceived professionalism of LMHS and overall opinion of the service. Analysis Responses to the structured questionnaire were analysed using descriptive statistics and latent class analysis. Free-text responses were transcribed verbatim and interpreted using thematic analysis. Results 184 people responded to the survey. 147 were service users and 37 were partners, friends or family members of service users. Only 31% of service users and 27% of close others found their overall contact helpful. Latent class analysis identified three clusters − 46% of service users generally disliked their contact, 36% had an overall positive experience, and 18% did not answer most questions about helpfulness or usefulness. Features most frequently identified as important were the provision of a 24/7 service, assessment by a variety of healthcare professionals and national standardisation of services. Respondents indicated that the least important feature was the provision of a separate service for older people. They desired faster assessments following referral from the parent team, clearer communication about next steps and greater knowledge of local services and third sector organisations. Conclusions This survey identified mixed responses, but overall experiences were more negative than indicated in the limited previous research. The evaluation and adaptation of LMHS along the lines suggested in our survey should be prioritised to enhance their inherent therapeutic value and to improve engagement with treatment and future psychiatric care.