Edinburgh calling

I was taken aback to see this on Queen Street. I didn't think there were any phone boxes left and I'm pretty sure this one hasn't been here very long. I didn't want to show too much curiosity, but I was tempted to open the door and have a peer around. It seemed to have a card slot in it which I guess makes sense these days.
I wonder if young children even know what it is, in these days when fewer and fewer people have landlines.