Background The COVID-19 pandemic has drastically increased demands on healthcare workers (HCWs) leaving them vulnerable to acute psychological distress,burnout and post-traumatic stress.In response,supportive services in a central London hospital mobilised mental health support specifically for HCWs.Aims This rapid evaluation assessed HCW psychological welfare during the acute phase of the COVID-19 pandemic and their use of supportive services made available.Methods During the acute phase of COVID-19 (April to May 2020) all staff working for the hospital were invited to complete an online survey assessing well-being (self-rated health,moral distress exposure,symptoms of burnout and psychological distress) and use of available supportive services (awareness of,use and perceived helpfulness).Associations among personal characteristics and psychological well-being were explored using correlations and linear regression.Results A total of 1127 staff participated in the rapid evaluation.On average,psychological distress was high(mean (SD):22 (7.57)) regardless of role,with 84% of this sample scoring above the general population mean (14.5).Nearly half of the sample reported feeling emotionally drained and a profile emerged displaying higher levels of psychological distress and burnout in those who were younger and exposed to morally distressing situations,with this group also exhibiting greater support service use.Greater levels of burnout were associated with increased psychological distress when controlling for personal factors.During this acute phase of the pandemic,majority of staff used at least one service and rated it as helpful.Conclusion HCWs experienced high levels of psychological distress requiring continued support as the COVID-19 pandemic evolved.Although HCWs were aware of supportive services,uptake varied.In order to mitigate the risk of burnout and post-traumatic stress,long-term,effective strategies that facilitate staff accessing support are urgently required.