The national grid is everywhere! All the power lines you can see above you and all the electrical sub-stations that you might have seen are all part of the national grid. There are probably a few control stations dotted around, the main control station is in Wokingham, I think.
Yes, the national grid is all around us! In fact, through the electricity system almost every electrical device in the country is connected! The grid is designed so that even if one part fails, the electricity can flow around the failure and fill that area of the grip from another route. This is called ‘redundancy’ and helps keep the lights on in your house 🙂