The concept of personal security has existed for thousands of years at the very least. Ever since human beings started to settle down subsequent to the discover of farming techniques that facilitated the creation of settlements rather than wandering nomadic tribes, a social hierarchy was formed which made it necessary for the higher ranking members of these hierarchies to acquire personal protection in some way, shape or form. This is something that is still true in the modern era at any given point in time.
However, one thing that has changed is the kind of training that these protection professionals need to go through. A big part of the reason why that is the case has to do with the fact that the needs of modern security have become a great deal more intense and elaborate then they used to be, with advanced weapons starting to be used by those that might intend you harm. Hence, any residential security team in London that you might consult with would most likely have a team of security guards that have been fully professionally trained and licensed.
This licensing process will ensure that they have the skill level required in order to ensure that they can do all that they have been hired to do. It also creates a baseline level of qualification which these guards need to aspire to, and the training portion makes it so that their physical fitness can be put to the test. After all, there is no point to a guard that can’t chase after someone who has just tried to attack you, so it’s useful to find a team that has been licensed.