Are you sure it wasn't a handheld airwave? (The new ones with short arials can look a bit like a phone)
It doesn't matter what they are called, the old bill radios use the cellular network (ergo, it's a cellular radio....which is what a mobile phone is).
All that old cobblers about them being "specially trained" to hold a conversation on a hand held radio device is just that.....it's cobblers.
...am inclined to agree with you K. That's why certain Departments had dedicated drivers - C8 and so on - to do nothing else but drive.
When I was being driven I ensured that the driver did precisely that and only that.
Irrespective of the demands placed on current officers, there is no excuse whatsoever for the driver to be doing anything else but driving and if they are, then they should be prosecuted and disciplined.
That sentiment includes single officer vehicles where an always-on voice link or other telemetry does not exist. In fact the very confusion over this matter suggests to me that amongst other things, police vehicles should by operated by a two person crew at least.