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OBJECTIVE This study was undertaken to determine contemporary trends in the use of the Twin Block appliance among UK orthodontists, including the wear time currently prescribed. In addition, the study explored if there had been any change in wear time prescribed, considering recent research evidence proposing part-time wear. DESIGN Cross-sectional, online survey. PARTICIPANTS Members of the British Orthodontic Society (BOS). METHODS The questionnaire was emailed to all BOS members in November 2021 and hosted on the QualtricsXM platform. The questionnaire was piloted for content validity and tested for reliability. RESULTS A response rate of 19% was attained. Nearly all (n = 244, 99%) participants used the Twin Block, and 90% (n = 218) prescribed full-time wear including/excluding eating. Although the majority (n = 168, 69%) had not made changes to their wear time prescriptions, nearly one-third (n = 75, 31%) had. Those who reported a change in their prescriptions currently prescribe less wear time than before, and commonly quoted 'research evidence' as the reason. A wide range in success rates (41%-100%) was reported, with patient compliance as the main reason for treatment discontinuation. CONCLUSION The Twin Block is a popular functional appliance among orthodontists in the UK, originally designed by Clark to be worn full time to maximise functional forces applied to the dentition. However, this wear regime may place considerable strain on patient compliance. Most participants prescribed full-time Twin Block wear excluding eating. Approximately one-third of orthodontists made changes to their wear time prescriptions during their practising career, and currently instruct less wear time than before.