Traffic lights not changing from red

I was just leaving kirkstall bridge shopping centre and it seems the traffic lights leading out were stuck on red. Myself and a few other cars approached the lights whilst they were already on red, and were sat there between 2-3 minutes and they still didn't change. I have gone through these lights on many occasions and I know they don't take that long to change usually, it definitely seems like there was an issue with them moving to amber and green.