The story says:
Apple’s agreement with O2 is thought to include a continuing share of the revenues generated by each iPhone customer. O2 ’s network will also have to be specially configured to accommodate the Apple handset. The lure of the Apple brand is expected to lead thousands of UK mobile customers to ditch their existing contracts and switch to the iPhone provider.
It also claims that O2’s rival Vodafone pulled out after deciding “that the commercial terms on offer were not viable”.
The O2 press office wasn’t answering the phone when I tried calling just now to get comment or confirmation. Maybe they’ll get back to me after they’ve checked their visual voicemail.