No cameras due to anti-terrorism laws?

I can understand but I'm a little bit confused. But basically I'm working on my college project and decided to create a time-lapse of various places around my city centre and today I set up my GoPro upstairs on a shopping centre that opened a few years ago and is very popular.

But a member of staff approached me and asked if I was taking photos or recording video, I said I was doing this time-lapse for my project and he told me I wasn't allowed to due to anti-terrorism laws. He was polite and I explained what I was doing and I apologised for any inconvenience and turned it off and moved on.

But I was a little disappointed as that was one of my favourite locations I wanted to visit. I was only testing things today but was hoping to go back with my main DSLR and tripod next time but by the looks of it I can't.

But I'm just wondering if I was in the wrong? After all it is a public place and the centre itself is partly closed and partly open anyway so should I be allowed? Or would it just be best to move to some different locations?

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