It is very atmospheric. Mostly set in a rural hospital surrounded by leafy forests in which a crashed alien craft is discovered by a very UNIT-like set of troops. A mysterious figure is taken to the hospital after it is run down by accident by a swinging couple(Its an odd and very British mix of science fiction and kitchen sink drama.) Various medical tests reveal the patient to have unearthly origins and before too long the hospital is further isolated by a force field set up by the alien figures who are in pursuit of the patient who is no innocent visitor from beyond the stars.
British character actor Edward Judd plays the over worked melancholy doctor who discovers their patient is not all they appeared to be to begin with. (The odd plastic/rubber outfit worn by him is a dead giveaway.) Edward Judd had a good line in world weary seen it all before types and his character is a ferocious smoker. He practically chews the smoke from his cigarette. Shocking bad habit for a medical man. One would think he would know better.
Cheekily enough I also saw some other shared themes from a much later Doctor Who story. Smith And Jones, which introduced the lovely Martha Jones to the many worlds of Doctor Who. When the Judoon transport the hospital where Martha is an intern to the surface of The Moon in order to isolate it so they may track down their alien quarry.It is much the same as the technique favored by the aliens in INVASION. Although the Judoon win hands down when it comes to visually representing how an alien life form might appear. The aliens in INVASION are basically just Asian people in futuristic jump suits, like the hench men of Dr No.
No one I have spoke to since watching the movie remember it but they are all familiar with the themes. It is so often the way with some of these wee obscure and quite forgotten gems...
