Aims The aim of this study is to evaluate whether there has been a significant change in the frequency of markedly decomposed bodies having coronial autopsies since the UK’s first COVID-19 lockdown.

Methods We compared coronial autopsies (n=263) performed by one pathologist at a central London mortuary in the 1 year before and after 23 March 2020 by analysing their autopsy reports and coronial documentation.

Results We have shown that there has been a significant increase of 70.5% (p=0.001) in the frequency of markedly decomposed bodies having coronial autopsies since the first lockdown. This is associated with a 38% increase (p=0.0001) in the rate of those dying at home and a 52.4% decrease (p=0.00003) in the rate of those dying in hospital who go on to have a coronial autopsy in our facility. Our results suggest that the most significant factor behind the increased frequency in advanced decomposition change since the first lockdown is this increase in coronial autopsies for deaths at home relative to deaths in hospital.

Conclusion Our results support the idea that perimortem social isolation will lead to an increased frequency of advanced decomposition changes seen at autopsy. We suggest that it could be possible to use the frequency of advanced postmortem decomposition change in a population as a surrogate marker for social isolation in future studies. Our study also illustrates a changing environment where the increasing prevalence of postmortem decomposition changes could affect the accuracy of autopsy reports and the medicolegal consequences thereof.