Like most of you, I'm inundated with spam calls. So I have a new solution. When an unknown number calls me, they get routed to this audio file.
This was created with Amazon Polly which is free for casual use. I was pretty impressed with the voice quality. Although there are limits to how well you can control the speed and intonation.
While there are a number of accents available, there are only a small number of distinct voices in British English.
Type your text, choose your voice, listen in the browser, then download the audio.