My original tumblr post was here. This image was researched by Bacchus at ErosBlog as part of the “Δ commission.” The research was originally published at Hedonix as Δ 044 – Fond Farewell To Daleks.” Here is what Bacchus found.
The Tardis Data Core wiki about the long-running TV show Dr. Who informs us that actress Katy Manning (who played the Doctor’s companion Jo Grant in the early 1970s) later posed nude with a Dalek for a magazine:
In 1977, she posed naked with an original Dalek prop for the glamour magazine Girl Illustrated (Vol. 8, #10). She laughed the furor off, stating, “You’d have to pretty well put me under a microscope to see anything!” Upon being informed of the photos, Jon Pertwee was quoted as saying, “Typical Katy!” In a later interview, she stated that the nude pictorial “went over like a cup of cold sick.”
The Wiki article where this information appears contains a color photograph (evidently the first page of the magazine shoot) showing Ms. Manning in a different pose but wearing the same fancy boots:
The visible text reads: “Kissing The Daleks Goodbye: Katy Manning talks to Tym Manley.”
A fortuitous eBay auction gives us a higher-resolution image of a similar pose from the cover of Girl Illustrated, along with the first few paragraphs of text from the magazine spread:
A different eBay seller’s auction text, preserved on a magazine collector’s blog, gives us a verbal description of the rest of the magazine spread:
The pictures of Katy include 6 poses, including a centrefold. Katy Manning was pursuaded by the Australian men’s magazine to do the feature, much to the shock and anger of BBC management at the time. They had managed to get hold of a Dalek and the darling young Katy in the buff (and in one shot with only a pair of knee length boots) made a perfect match for the most dangerous machine/creature in the universe. She commented that news of her photo shoot went down ‘like a cup of cold sick’ with the BBC Managers.
Although no complete scans of the magazine or the Katy Manning spread from it appear to exist on the web, a couple of forum posts here and here (both are incomplete, with missing images due to lost image hosting) combine to give us some idea of rest of the contents, possibly including these two additional nude-with-dalek images:
A blog post here offers another pose where Ms. Manning is actually straddling the Dalek’s appendage:
And finally, at Слава роботам! we find one last related image:
To sum up, the best available description suggests that the Girls Illustrated photo spread included only “six poses”, of which at least some were centerfold-type pictures not including the Dalek. Yet here are compiled a total of seven different photographs of the same actress in the same boots posing with the Dalek prop. The only supportable conclusion is that at least some of the additional photos taken when the Girls Illustrated spread was prepared were published later and elsewhere. It has been impossible to determine whether the subject photograph was one of these or was originally seen in Girls Illustrated. But since every indication is that Girls Illustrated was a full-color magazine, most likely the subject photograph originally appeared elsewhere.
In the course of this provenance research, an older-looking, unrelated, and utterly unattributed photograph of a topless woman posing with a Dalek turned up in a tribute to the designer of the Daleks:
