Alkathene sizes

Good Evening all,
Could anyone please tell me when black alkathene started being used on incoming water mains?, and approximetely when did it all change to blue metric mdpe?
I live in a 1950's bungalow that has a 21.5 o/d black alkathene,and the i/d is only 11/12mm, I know this because I changed my leaking stop tap to a 22m one to accomadate the alkathene pipe, useing a 3/4"olive,not useing a insert because the walls were that thick. Thanks.

Poly york pipe, 1970s, made by IMI YORKSHIRE, now PEDLER YORKSHIRE

amstel said:

using a 3/4"olive,not useing a insert because the walls were that thick.

Click to expand...

You need insert in it, otherwise stopcock will pop out of pipe slowly under pressure, trust me, I've seen it before with missing liner / insert.

Daniel.