A slightly different perspective....
I know we all feel bad for everyone involved, from the worst case of people losing holidays or PODL to the guys just facing some extra time in a horrible transit block in London.
However, I've noticed some people on other forums I frequent saying how glad they are that G4S have screwed up; because they'd much, much rather have the military acting as security than whatever dross G4S can dredge up with a terrible contract!
It's ridiculous, and in some situations it's totally disgraceful that the armed forces are doing this. But as a silver lining, from what I see, the public will be extremely glad to see someone in MTP acting as security rather than someone in a G4S uniform.
Well done to everyone doing their bit.