I think it was the weather that prevented pollination. Hope its better next year. I have four apples on two trees - you are not alone!

We have none on ours this year. Definitely the weather.

When I had apple trees in another garden they sometimes missed a year - one plentyfull year was often followed by a hopeless one. It's as if they're taking a rest after producing so many apples the previous year.

if you had blossom then the weather at the time of pollination would have stopped any pollinating insects doing their job.

Thanks gardeners, will give son the answers tomorrow.

As said, weather at blossom time, mine are the same, so it's some consolation to know we are not alone

Fruit trees can get into a "one year on, one year off" cycle which is probably what has happened. It is difficult to break them out of it, but you could try drastically thinning the fruit in an "on" year

Was the weather unusually cold at blossom time?

yes it was cold and wet.