This is probably evidence of bad pricing practices on the part of UK (and other EU) mobile carriers. Sure, when it was brandy-new technology and every mobile second was precious, they could justify those rates, but nowadays it's just a ripoff, using the terminating monopoly to gouge CPP.
Here in the US, mobile usage is skyrocketing. Most people are on block-of-airtime plans, which often exempt in-network and off-hours calls. Some smaller carriers now provide totally unmetered service, which is popular with young people who don't even have a land line. (Land lines here are also usually unmetered, at least for "local" calls.) The result is that wireless carriers in some markets are generating more minutes of use than the wireline carriers!
I think a lot of the growth in the US is due to the wireless carriers' generally competitive mindset. Most markets have about four carriers, just enough to keep them on their toes. (FCC Chairman K-Mart is trying to get that down to three, so they can become monopolistic too, but fourth place T-Mobile is doggedly fighting on.) Wireline providers are less competitive here. And it sounds as if wireless providers in Europe are more interested in gouging for what minutes they can sell rather than in really competing hard.