Germany imposed lockdown when they had about 58,000 infections, whereas the UK locked down at about 260,000. Those figures are from ICL’s model, and they’re estimates for all actual infections rather than just those tested or otherwise diagnosed. But ICL’s model seems to be very good at predicting death rates in multiple countries.
Sweden, and to a lesser extent Belgium are the ones to watch. They haven’t yet got the reproduction number Rt below 1, so their epidemics are still increasing.