Encourage bees. Cant think of any other way really. People often grow sweet peas along side the beans to encourage bees. Cant really think of much else...

Spray the flowers with a water mist spray early in the morning, or last thing at night. This should help pollination.

Or even take a cheap artists paint brush or a q-tip and tickle the flowers :-)

I was wondering about something along the same lines as Gerry's runner beans have no end of flowers but only a bean or two! But as I was watering them today I saw that at long last they are now beginning to form! I had thought of asking here but it looks as though it will no longer be necessary.

Its the heat, Balcony- there've been so many questions this year in various places about beans not setting, I did a bit of research - runners apparently don't like very hot weather, so the beans don't set. You may getting them now because the weather cooled off a bit a week or so ago. There are other causes, but its such a common problem this year, that the heat is the obvious one.

Oops i blamed the mice for disapearance of the lower beens. Sorry mice!

I thought it might have been lack of water so I've been watering them more often!

That's a good thing to do Balcony, because that's another critical factor.