PEOPLE OF THE UNITED KINGDOM
The humans altered by Respirazon are commonly referred to as "Infected" by most people. It is known that they are feral with a level of pack mentality, grouping together with one another and forming their own basic hierarchies. They are omnivorous and will turn cannibalistic if needed against both Infected and Healthy humans. However, this is not seen often, as it appears the creatures do not need to eat very often. Some people claim it takes months for one to starve to death, while others claim it's far longer, so where the truth lies is not common knowledge.
Some of the Infected seem to retain some basic levels of intelligence in regards to use of tools and motor skills. They understand basic concepts such as how to wield a basic weapon, or how doors work. They are not the mindless zombies that people were first reporting, and this makes them that much more deadly. The intelligence level varies between Infected, and most folks seem to agree that they are 'caveman-like' in nature.
They seem to operate on various forms of non-verbal communication, though no success at replicating this has been noted to date.
Those humans who were unaffected by Respirazon are commonly referred to as the "Immune". No-one is quite sure just how many were immune to the mutated cure, but humanity is now far from the dominant species on the planet. As far as anyone can tell, no other creature was affected by the mutated Respirazon drug.
The Immune began to band together where possible for safety and sanity, with those making groups and communities faring far better than those who chose to try and survive alone. Over time, within the UK, a few more well-known communities have been established, which many people know by name.
It's unsure whether this is a rumour or true, but many people claim that some of the original scientists and chemists of Panacea Pharma within the UK survived the Respirazon release, and are still actively working on the drug. Some claim they intend to try and cure the Infected, while others believe they intend to wipe them out. No-one seems to mind which option is true, ultimately! However, if Panacea staff are still out there, no-one is sure where, or how many of them.
THE UNITED KINGDOM ARMY
Founded by a handful of surviving army officers, who recruited wherever they could, the United Kingdom Army (or UKA) are a known force within the UK. Yes, they are very limited in number, but where they exist, they make their presence known. They have several bases around the country that are heavily fortified. Some even claim that they still have firearms, which no-one is stupid enough to want to test the validity of. Small communities tend to crop up close to UKA bases and benefit from their protection, though also have to live under the rules of the UKA for the privilege.
Sadly, even at times where humanity would be best served working together, there are still always those who prefer to rob and steal to get by. Even now, this remains true. Commonly referred to as Highwaymen, these are Immune people who prefer to prey on travellers rather than make anything of their own, and are pretty dangerous individuals. That said, they are still rare, as all humans are, and many are hesitant to kill them in case they have some special skill or ability that could help an established community, if only they could be convinced to change their ways.
ANGELS OF THE NORTH
Some wanderers referring to themselves as The Angels of the North have been sighted across the country. Usually moving alone or in groups of two, they claim to be part of a community near Edinburgh that is seeking out the best that humanity has left to offer to create the start of a new British civilisation. They claim that the location is safe, with water and electricity, and is an invite-only haven for those deemed worthy. They speak of it's leaders, Lord and Lady Graysen, with admiration bordering on reverence.
THE NORWICH HEALTH SERVICE
Also known as the NHS, the Norwich Health Service was set up by individuals who once worked within the National Health Service and believed in it's commitment to free healthcare, wanting to ensure it's legacy lived on even after the Respirazon cure. They operate out of the centre of Norwich city, and often recruit other doctors and scientists to join them. Some small groups travel across the UK to trade and find new members, and a small number of them are dedicated to trying to find a way to slow or even reverse the Respirazon infection. However, their primary acts are to continue the production of medication as well as provide medical services for those in need.
THE MARAUDERS - CLOSED TO NEW MEMBERS
In this new world, people will find solace in just about anything. The Marauders are one such group.
A set of people all under the age of forty, the Marauders have found solace in the fiction, and in particular the tales of one certain wizard and his adventures against the evil Dark Lord. Members of this group all name themselves after various characters from the books, and travel the UK in search of "The Chosen One", who they believe can still perform magic and will defeat The Dark Lord (whomever that might be, no one is quite sure). They seem to have blurred the lines between fiction and non-fiction, and while they come across as quite quirky, they've not gotten this far without developing some pretty solid survival skills.
THE GARDEN OF EDEN
The residents of Penrith in Cumbria have re-named their town The Garden of Eden, named after their district. They are an insular group of individuals, with a large number of older residents due to the fact that very few residents here contracted the Respirazon infection. They are a small community, but a very tight-knit one, and do not welcome strangers easily. They do trade, but largely prefer to keep themselves to themselves.
While there are setups in rural areas, it seems that most small groups have established themselves in suburban areas, out of the dangers of the larger towns and cities, yet still close enough to them to scavenge there for supplies. Most are people simply trying to survive, while others may have more elaborate setups. It can be tough to find these locations as, for the most part, many communities once they are established and surviving do not want to be found, for fear that newcomers may ruin the tentative balance they have achieved.