In reply to Goucho:
On one of my first times climbing at Llanberis my leader got a bit lost, it was his first year climbing too, and kept on going with hardly any runners until the inevitable happened. It was the first pitch and luckily the rope, single 9mm perlon, snagged, stripping the outer core off completely... leaving only the inner holding.
He ended up dangling about 10 feet off the scree - large blocky stuff, and I was pulled off my feet as he was 11 or 12 stone and at the time I was about 2 stone lighter. There was no difficulty holding him with a waist belay, no burns as it was winter so I was wearing a thick pullover, or something similar, both of us were tied on directly with an ordinary bowline. The fall must have been about 100 feet. I don't think he came climbing after that.
It convinced me just how strong ropes are as this was one that should have been used double, back in 1970 so they must be even better today. It also taught me to put in runners where possible and to avoid just going on up when you are lost