Summary from growing overground on another thread.
In brief, it says if we do nothing, they predict 80% of the UK will be infected and 500k will die and the peak will be in 3 months. It also suggests that modelling attempts to mitigate the epidemic and flatten the curve, as the government was trying to do until today, will not work as the healthcare system will be overwhelmed but might reduce deaths by half. As the government has been saying, if we were to aim for mitigation, that should be delayed until close to the peak.
It concludes, however, that the only viable strategy currently in the UK is suppression, making sure that each infected person infects no more than 1 other person to keep the epidemic under control. To do that, it needs to be done now, the entire country needs to socially distance, home isolation of cases, household quarantine where there is a case, and closure of universities and schools. This may well need to be done until there is a vaccine available (potentially 18 months away) although suppression may be possible by other means in future months in the way that South Korea is managing the epidemic with intensive testing, contact tracing, quarantine, phone tracking etc. It also recognises that such long term public health intervention has ever been done before.
It is not government strategy though, it is a scientific paper that the government has used to advise them. As we saw today, most of the suppression strategy has been implemented.