With the new Omicron Covid-19 variant it would appear that this is more transmissible than earlier variants, but indications (early) are that it is less severe. For most people it presents a bit like a cold, not needing hospital treatment.
With luck, this will soon become the dominant variant and herd immunity will result in the virus subsiding. There is a risk still that hospitals could be overwhelmed, so the UK government has taken measures to slow the growth. It seems inevitable that this variant will soon be the dominant one.
Recently rumours have emerged about parties at the UK Prime Minister's premises in Downing Street last Christmas. These have always been denied, but they are being investigated.
What seems to be true is that the UK people largely follow the Covid rules despite the government rather than because of them.
Government credibility would be higher if they always led by example.
Clearly any gathering carries the risk of spreading the virus.