I have been working for G4S for nearly a year now, and one thing you are promised is a healthy work and social life balance, that is not true, my slow week is 58 hours and my longest can be 60-70 hours, this is all on minimum wage as well, my contract is the lowest paid, even though other buildings on the same contract are paid more for doing the exact same job as myself and the other guard(s) in my building.
When you go to the interviewer, he or she rants and raves about how quickly you can move up the ranks in G4S, absolute lies, you are stuck where you are until you are no longer required. I have worked with people who have been with G4S for 15-20 years and have never been offered promotions, or even a chance to advance their career within the company. The job is okay for a stop gap, while you figure out what you want to do, but I would not recommend it as a career builder as you will be stuck like the hundreds of other security officers that have been promised career development. Luckly I am young, and eager so for me G4S is only a stop gap until I finish of other security courses to progress my career.
Management is a shambles, I see my manager once a month, if that. There is no real communication within the workforce, it's hard to even get new uniform.
Unless your moving into a supervisory rule or management role, I would not recommend joining the company, especially if you are young. The job is okay for people nearing retirement age.
Get to meet interesting people, pay is on time
Long hours, minimum wage, management is awful, no career development.