The GC has given you duff advice, to the best of my knowledge no ilex is self pollinating. You need a male and a female tree.

The variety you have is, fortunately, a female, which will produce berries, but it seems you're unlucky in that there are no male hollies in the vicinity, either in your garden or anyone else's. You may need to buy a male holly to plant somewhere to ensure berries - be careful what you buy, make sure the one you choose is a male and not female.

Thanks Bamboo, I meant to say that!

But both the male and the female flowers are white so you really need to look at them closely and then copy and paste this link into your browser to see which you have:

http://bit.ly/jInMee

so difficult to tell from the flowers that it's safer to buy a named variety - the names dictate which sex the plant is, although its still not easy - Ilex Golden Queen is male, Ilex Silver Queen is male.... But the variety you have is definitely female.