Violent crime is on the decrease as a whole. While this is an awful incident, it is not part of a pattern of increasing violence or an epidemic of violence. Britain is not "getting worse" but coverage of incidents via rolling news coverage, sensationalist reporting, and social media rent-a-gobs make you think it is by shoving negativity in your face 24/7.
I agree with points made about the mental health crisis, lack of funding for family support services, parenting, etc. These are all areas which require attention and link to issues which need to be addressed, particularly those relating to VAWG.
However, an isolated incident is not indicative of the imminent downfall of society.