Prestel was a viewdata/videotex service in the UK. Similar to Teletext except the data transfer is both directions.
The user connected to the service through a RS232 interface and a modem.
The service had various areas.
There was an area dedicated to the Amstrad called "Amster's Cage" it was run by Vince Merrill. First it was on Micronet 800 and then later was part of the "Silicon Village" in 1993.
The service had news and software that could be downloaded.
Cirkit made a hardware addon to offer this service to the CPC.