//...four people sat around a table in a garden.//
Indeed. But that's precisely what, at that time, much lesser mortals were prevented by law from doing. They we enforced under threat of financial penalties which, if unpaid, could result in a criminal conviction and if still unpaid, committal to prison. There was a chap on the news yesterday who had been issued with a fixed penalty on the very same day as the No 10 gathering, for having three friends in his garden for a beer. Even more galling than that and as I have touched on earlier, those same lesser mortals were prevented from "gathering" for more reasons than just a frivolous drink and piece of birthday cake. They were prevented from gathering with a dying relative or with family members who could do with their company and who suffered mental anguish due to their isolation. I don't really know how much more I can explain this.