The 4th Bomb

I entered Vauxhall underground station and walked past an LT employee.
‘Oi! You’re not allowed that in here!’ she said sternly.
Huh? what’s she on about? I wondered.
Was I holding something combustable or a suspect rucksack?
No, I was fiddling with my mini-camcorder’s light exposure setting.

I thought for a moment as I descended the escalators to the platform. I have upgraded my digital camera since the the aftermath of 7/7 and rarely leave home without it.
Was there a specific act that deemed the carrying of devices capable of recording digital footage a threat to society?

I understand that in places like Saudi Arabia this may be the case for cultural reasons. But why is the United Kingdom veering along this path? After all the U.K has more surveillance cameras than anywhere in the world.