As an O2 customer I have always incurred call charges ringing my Three customer wife. Those days are gone now as we are the one network now. I did ask O2 a few weeks ago about this but they were unsure. From looking at my itemised bill, my wife call charges stopped mid February. That is quite a good outcome for me as most of my monthly cost was to her. Although the changeover has been well advertised, I was completely unaware of the cost elimination until this morning.