Lead-in line to the lead mine!
Magpie lead mine (disused) in the Peak District
Funny thing this English language. There are lots of words which are spelled the same but sound very different. LEAD is a classic example:
Lead (pronounced "leed") means to show the way, go first, guide etc.
Then there is the chemical element lead (Pb). This is pronounced "led" but led is a word of its own. In fact it is the past participle of lead ("leed") LOL! Confused yet?
I had an idea as I was writing the description. Surely if it is magpie mine it ought to be in black and white shouldn't it? Shame it wasn't a cloudless sky, then I could have left a little patch of blue too! LOL!..........;-)