It was common in the 1970s to have shared lines. If you were lucky you shared with one or two other people, others shared with quite a few.
I wonder what stories were heard by some people.
My Mother In Law shared a phone line and wanted to use the phone. After the second attempt she turned around and said "hurry up on the phone, you have been on over an hour. I'm waiting to use my phone"
Here are some comments from our Facebook page about shared lines.
Chris says " We had a blue one and yes we had a shared line. It was a right pain"
Ken says "My Sister had a shared line"
Angela says "We had a red one, Mum and Dad had a blue one. There was a shared line for awhile"