Slugs/snails are the most likely, they love 'em.

I would agree..

Thanks, but I don't think so in this case, because those little grey flecks on the stems and the soil look as if they were insects of some description or at least are the cases of something that was alive....
I've also added another photo of a lupin that's going grey-not through age, like me!--but just going grey.

I just found this:
http://apps.rhs.org.uk/advicesearch/Profile.aspx?pid=653
and wonder if this is what is eating my lupins?

That one looks like Mildew to me,Canalhopper..I hide my grey :o)

They look like aphids all over the stem. Wash 'em off!

Definately aphids on the stems. They will suck the sap and weaken the plant but not chew the leaves as in the second picture. I would suggest slugs/snails for this and your plant is under attack from two different sources.

Agree with the aphid infestation and the mildew... so three problems, mildew, aphid infestation and slug/snail, as everyone else has said. Try the milk spray for the mildew (1 part milk to 9 parts water).

Thanks to everyone for the help, which has been acted upon.