No, no loosening, but apparently the shift is due to a change in intimate/spouse murder. Those are most often committed by hands, knives, and blunt instruments, and probably form a sort of baseline homicide rate. That rate has obviously been much lower in the past, or else many murders were going undetected (pillows, poison, blaming it on a staircase fall?)
The DOJ and UK homicide stats get broken down into relationship, method, etc, so it might be interesting to see if something seems like it was missing, such as a jump in a particular type of homicide as a particular new forensic method or focus was introduced, such as getting more people to report abuse.
Sometimes you find interesting things in crime statistics, if you bother to dig into them *looks at room and coughs*. A few years ago some US police departments were curious as to why they were personally familiar with so many homicide victims. Baltimore cops were surprised that 91 percent of their victims also had long lists of prior arrests for violent crimes. Other cities checked, and generally 75 to 90 percent of the homicide victims really didn't belong on the streets, usually having about a dozen priors and apparently engaged in either turf battles, drug disputes, or previous homicides and assaults.
Unlike Western Euope, the US still includes what you might consider as ongoing, small scale (and large scale) crime wars, which includes something quite close to a feuding or dueling culture. In Europe, Appalachia, and the Old West, that had to basically burn itself out, though there's a lot of thought, and a whole lot of ink, digging into the causes and potential remedies.
Our current approach is to maintain a prison population that outnumbers Latvia, with all of Norway on parole or probation. Violent behavior usually peters out as people get older, and the biggest correlation is being a young male in an honor culture, such as Shakespeare's Romeo (period accounts bear that out. Most rapier deaths were teens).
The UK numbers have almost nothing to do with guns (they didn't have much of a homicide problem even before they cracked down on guns, and used to have a fanastically high murder rate with knives when King James was on the throne), but they did see a rise when UK teens got into US gang style coolness. Tiny changes in young male behavior completely dominate murder rates, because that demographic in the US is 20 to 300 homicides per 100,000, rates you can hit without any guns at all if teens decide that knife fighting is cool and manly, as Italians did up through the early 20th century.