My fascination with the tube is never ending and I was quite chuffed to find this random installment about the Northern line that never was, nor will be. I had been mildly intrigued as to why the line has a little bit that is Mill Hill then it disappears into nothing. So now I know.
I am going to keep my eyes open for new videos, as of course this is not an isolated case. If you have a bit of time have a watch.