Very serious incident this. The wind wasn't *that* strong, so there's a chance this could've happened with fans in the ground and a game going on. The consequences could've been catastrophic.
The pylon in question appears to have failed around the first joint (each light has two joints, with the first doing most of the heavy lifting). Suffice to say, if this is found to be an issue with the design I think the remaining three might also need replacing with a less elegant, but more robust, design. The ground has been designed for the lights to sit outside and curve in though, so this might be a tricky one to resolve! Just pleased no-one was injured...