David Hill wrote:
I thought the entire* point of runner beans was to leave the roots in
so that the nitrogen-fixing nodules of the roots conditioner the soil
ready to make it your brassica* bed next year.

If the entire reason for growing runner beans was to fix nitrogen then
you would grow something like clover or alfalfa instead, much less work
and more nitrogen fixed.

Well, ok, not the /entire/ point (hence the *). The point after the main
point, ie, eating the beans.