Welcome to Dad’s Secret Stash, where we take a look back at some of the naughty pictures our fathers probably had stashed away in their sock drawer.

This photo, snapped on June 16, 1975, shows office girls stripping down to their underwear during lunch to sunbathe in St. Jame's Park.

Even though the world has come a long way in the 37 years since this picture was snapped, there is no way a group of women from an office would strip down to their underwear on a lunch break. Especially, in a world with Facebook, Twitter and high powered cameras. They'd all be fired after lunch.

Also interesting to note, in the background of this photo and far from the camera lens, the men from the same office have stripped off their pants. Pretty sure they weren't sunbathing.