I don't remember Britain having any online services before the web, what are you referring to? There was Ceefax....

We had Prestel and Micronet (a form of viewdata; Micronet was hosted on Prestel, but was frequently the reason people signed up for Prestel in the first place), and there were also individual BBSes available.

Of course, we also paid for local calls so things never got as popular as they were in the US.

I think that would be Prestel. The fact that you don't remember it probably tells you all you need to know...