Old plastic/ rubber pipe and compatible fitting?

Hi, a stopcock has seized and I need to replace it but the pipe is an unusual rubber/ plastic material. It’s approximately an inch ID. Has anyone got any advice for replacement compatible fittings? Will it need inserts etc?
Thanks in advance and some pics below.

Black alkathene, very hard to get hold of fittings for this pipe , look at a philimac utc .

In the early 80's all materials supplying underground services were black, gas, water pipes, electrical ducting were all the same colour. This caused lots of problems when roads were dug up to access underground services as due to their similar appearances, it was almost impossible to identify what was what and mistakes were commonplace, with people cutting into the wrong pipe.
Thankfully, colour coding came into place and gas pipe became yellow, and water pipe became blue.
There are differences in the outside diameters between alkathene and modern mdpe, but there are universal adapters available with the best (in my opinion), being the Philmac range. These have adapters that fit just about everything including alkathene and lead pipe.
Information is in the link below, should you want to take a screenshot of it and take it along to your local plumbers merchants.