Gardening_Convert wrote:
My runner bean doesn't seem to be setting fruit after flowering the
flowers are just dropping off.

Like the others say, lack of water.
Runner beans can fruit quite late, so it might not be impossible to
rescue something for this year if you can convince it it's younger than
it is. Water it quite heavily and remove all trace of failed flowers
and it might try again: you've nothing to loose but a bit of effort.
Bit of a long shot, mind.