I'd give them all a weapon and force them to fight to the last group of 10 for my own amusement.
This 10 would be the strongest, most ruthless and with the best survival instincts, who shall then become my personal retinue.
Then I begin to brainwash the disaffected youth with my illusion of power and the ever present threat of my enforcers/bodyguards, possibly using the internet, appealing the socially inept who feel alone and cling to some group to belong to (hey it's how most little cults work)
Then the crime spree and chaos begins, orchestrated by minions further down the chain of command, with me not being implemented in anyway for I am simply a shadowy figurehead who is never seen. Lesser minions may rat on those above them when caught, but once it reaches one of the 10, they are so loyal they will die before revealing anything, keeping me safe.
As influence spreads and more are "recruited" into the fold, the country will slowly burn.
After everything the UK once was ceases to exist, I order the 10 (If 10 have lasted this long) to kill themselves, I leave with my accumulated £££ and head off for a nice life in another country somewhere to see out my days.
Why would I do this? Meh, passes the time I guess.