Like the previous contributor, I was in my teens when this was first aired. And - also like the previous contributor - I remember the taxi scene vividly after the same amount of time. It's rare to find good SciFi, let alone brilliant stuff, but Out Of The Unknown contained some outstandingly good adaptations, and this was one such. The conversation with the taxi driver especially sticks in the mind since the 'mind invader' was 'chosen to be especially level headed' and the chosen character of a 'blunt northerner' worked very well, the kind of man who does not suffer fools gladly. In those days when the BBC in particular regarded itself as the guardian of the English language (how things have changed!) it was rare to hear any accent other than 'Standard Oxford English' on TV. Maybe the producer was thinking of the late great Professor Fred Hoyle as a model? And when the taxi driver is duly told to 'go to hell', the whole taxi promptly sinks into the desert sand! Arranging this with only the limited graphics and technology of the 1960's was something else again!