I think its Stapelia variegata, now called Orbea variegata, although the stems showing behind appear to be too red in colour - I'm guessing that might just be a trick of the light (if they're lit by, say, a setting sun...). Ceropegia haygarthii is similar and related, though the flower's not quite the same, but that one does have more reddish stems. I imagine the flower smells unpleasant, one of its common names being Carrion flower...

Hi, certainly looks like Stapelia to me , Derek.