This is the last of the five unreleased Rogue Trader era adventurer types that I've discovered in Bryan Ansell's collection:
The figure has "Trooper" written on the front of the slotta tab and is dated 1987 on the rear of the tab, so another very early Rogue Trader figure.
Whereas there has been some debate over potential figures of origin for the unreleased RT figures I have shown previously, the origin of this Trooper is in no doubt: it's "Old World Jack" from the Space Pirates/Mercenaries range (image from Collecting Citadel Miniatures wiki):
Annoyingly I dont have one of these Old World Jack figures near me as I write but I'll have to check the date on the base tab later. I'm assuming it has to be 1987 but wouldn't it be fascinating if it was later? That would mean the unreleased figure came first. Anyway, I'll update the post later tonight.