  The policies implemented to hinder the COVID-19 outbreak represent one of the
largest critical events in history. The understanding of this process is
fundamental for crafting and tailoring post-disaster relief. In this work we
perform a massive data analysis, through geolocalized data from 13M Facebook
users, on how such a stress affected mobility patterns in France, Italy and UK.
We find that the general reduction of the overall efficiency in the network of
movements is accompanied by geographical fragmentation with a massive reduction
of long-range connections. The impact, however, differs among nations according
to their initial mobility structure. Indeed, we find that the mobility network
after the lockdown is more concentrated in the case of France and UK and more
distributed in Italy. Such a process can be approximated through percolation to
quantify the substantial impact of the lockdown.
