Iron Hand is an agent with the British Secret Service.
Whether the department for whom he performs his highly impressive operations is MI-6 or a different, unnamed bureau is not revealed. All we know is he workes for Sir Adrian Glover who apparently holds a lot of clout and that Iron Hand is send all around the globe on behalf of his country.
Who Iron Hand is when not on assignment is never revealed. We learn nothing of his background or his training, zilch about his personal life or what he does for recreation. We do not even ever learn his name, first or last. Iron Hand is how we know him and how his boss addresses him when not using his codename of Agent 041 (not sure why the leading 0).
Also left totally to speculation is how he came to possess the steel hand that makes up his most shining asset. Unlike a couple of secret agents who have a metal extremity (Sarge Steel and the Steel Claw) we remain clueless as to what caused him to have it. We do not even know if it is a replacement for his real hand or some sort of fancy glove. The way he uses it makes me think it is a prosthetic but if so, it is a highly advanced one, bordering on if not passing into the realm of bionics.
Iron Hand (odd name for someone with a steel hand) can use the hand just like a normal one in that he can, and does, shake hands with it and can grasp items and use them as if it were flesh. It can bear his weight when dangling from somewhere holding on only by its grip. And being steel instead of its namesake, iron, it does not rust when exposed to water, something that happens a lot.
With his steel appendage, Iron Hand is able to perform some pretty amazing stunts despite not possessing any powers of his own. He rams the fingers into a gas tank, rupturing it. When needing to climb a rock wall, he smashes his metal fingers into it creating handholds. Another time he needs to slide down a powerline so he grasps the electrified wire and away he goes, all unaffected by the event. Naturally, being made of steel, using the hand as a weapon is a foregone conclusion and he does so on several occasions, rendering the victim instantly unconscious.
But that's not all! Press a button on the palm of his iron hand, an electric saw blade protudes from his index finger allowing him to saw through small trees and other shrubbery. Another button and the same finger (apparently) shoots a knock-out dart. Yet another button and that digit provides a mini-laser beam able to pierce thick steel. A different button and the finger shoots an inky black liquid creating a cloud underwater. Pushing a button on his wrist turns his whole hand into a powerful magnet, which he uses in the first adventure to pull a set of keys to him when he is locked in a jail cell.
It is obvious from his adventures and Iron Hand would have made a terrific operative even without his deadly appendage but with it, he is almost unstoppable.