The riggers that used to crawl into fuel tanks had my greatest respect. One job that I couldn't have done, the very thought of it makes me shudder. Hats off to you guys.
That was the domain of Sooties
Incidentally when building the Comet, one man was required in the wing to do up the fasteners, they had a in case of emergency cupboard that contained a concrete cutter so they could saw through the wing skins to rescue the trapped person.