In June 2016, the United Kingdom voted to leave the European Union. Since 2016 the UK Office for National Statistics has been reporting a positive but declining net migration of EU nationals. Given the uncertainty surrounding Brexit, this paper attempts to ascertain if a "Brexodus" is really happening, by using weekly estimates of European migrants in the UK obtained from the Facebook Advertising Platform. The anonymised count data are disaggregated by age, education, and country of nationality; the period of analysis is from March 2019 to March 2020. We use a simple Bayesian trend model with indicator variables for age, education, and country, to analyse the changes in the numbers of migrants. The Facebook data suggest a decreasing number of EU migrants in the United Kingdom. The preliminary results show that the largest migrant age group, 20-29 years old, is also the one that is decreasing the fastest over time.