I knew a second lockdown was on the cards before we’d had the first one. In mid-March my team at the University of Edinburgh modelled a lockdown that ended in June and was followed by a slow, initially imperceptible rise in cases over the summer, culminating in a second lockdown in late September.
https://www.telegraph.co.uk/news/2020/09/19/uk-needs-follow-swedish-model-learn-live-covid/