We assessed levels of post-traumatic stress disorder (PTSD) and post-traumatic growth (PTG) during the COVID-19 pandemic in the UK using an online questionnaire, in May and June 2020, during "lockdown." Some 440 participants took part and 91.8% of the sample was female. Large numbers of participants had high levels of PTSD, with some 50.2% with "probable PTSD". Yet 49.5% of participants also demonstrated high levels of PTG. Regression analysis revealed rumination to be key predictors for PTSD and PTG.