Then they flowers are not being pollenated. Spray with water to help this to happen - this is going to become a bigger problem as we lose more and more insects.

This must be one of the most asked questions every year. I've heard dozens of answers from misting the flowers with water, encouraging more pollinators, watering more etc etc.
I'm convinced this is just what runner beans DO most seasons, probably caused by dryness at the roots, or the conditions just not being right for setting 'fruit' (bean pods) because the plants aren't that well established yet.
You can do any of the many things suggested but as with every other year, the runners will start to set pods very soon and then you will have so many you won't know what to do with them!
My suggestion would be to grow climbing French beans, which set in dry conditions and tend to be earlier, and grow your runners to harvest in later summer and autumn when they do best.
Remember that the runner bean comes from cool, wet mountainous areas of central America.

Sorry MR, posted simultaneously with you.. but I still believe that this happens very frequently. I share your concern about pollinators but there really should be enough hover flies, bees and butterflies to do the job in this time of the season. I wonder if anyone has ever done controlled experiments on the non-setting of runner flowers? Mine are doing the same at present although they are covered with red flowers, yet we have eight hives of bees in the garden as well as huge numbers of other little bugs.

I agree Bertie, its just the nature of the beast, the same thing does happen every year until they "get going" someone on the adjoining allotment once told me that the bees sometimes nip the flower heads off, not sure if ture or not

Thanks to all for taking the time to answer,I will just have to be patient I suppose.

Ours haven't even produced any flowers yet!

The 'nipping off' of the flowers is where some bees don't have long enough tongues to get to the nectaries, so they chew a hole in the side of the flower to get access. If I remember correctly the ordinary large bumblebees have got tongues which are long enough but other types do the chewing (but not honey bees who I don't think bother with runner flowers, though I may be wrong.. never seen them on the flowers though.)