What we do know is that in the early 21st Century, at the height of the War on Terror and tensions across the world, that world ended. Weapons of Mass Destruction were deployed, detonated or released upon the Western world almost simultaneously. Some places suffered nuclear bombs, some biological weapons and others chemical agents. No one is sure of who planned the attacks, or undertook them, but shortly after the first strike the Developed World struck back. Their brute strength was swung wildly and without direction - and the whole world plunged into disrepair.
London, and most of Britain, was spared Nuclear Armageddon, but was afflicted with more subversive assault. The Capital had millions of gallons of Sarin gas released which decimated the population. Everything stopped.
Now it is years later, but who knows when. People live day to day, there is no government, no society like what was known. The capital has a handful of organised humans, holding their own elected borders, their own minor 'cities' as they call them. But most of the people live where they can, scraping whatever living they can from the wastes of history.
But the gas also left some people changed, and their offspring since. These people are debatable as humans. They are deformed, physically and mentally, and tend to stick to the darker, sub-surface domains.
Regarding Weapons and Equipment
Guns are and were generally illegal in the United Kingdom of Great Britain. Those to carry guns were the armed forces, special branches of the police, the secret services and country bumpkins like farmers and hunters.
In this world weapons such as this are sparse, most people have create crude weapons such as bows and clubs, the clever ones have made their own projectile weapons such as homemade harpoon guns. Be creative though as to what you carry, make it fit your character. If it is out of keeping I'll PM you and we'll work it out.
As for all other items of equipment and such, use common sense. Everything available will be derived from modern, 21st Century items. Once again, be creative with what you have and how it would look, and make sure you'd be able to get it in the UK!
