[ajb]

So giffgaff,who also use the O2 network, claim that they are unaffected as they have their own implementation of the service on top of O2s physical network. Which might be true, but I'm a bit suspicious as I know they are actually owned by the same company now,so consolidation is likely. If anyone tries replicating this on a giffgaff sim it would be good to know the result...

[signal11]

They've been owned by Telefónica for a while. IIRC Telefónica acquired O2 in 2006, and launched Giffgaff as a new brand in 2009.

[scoopyboy]

I've tested this on the giffgaff network, and it does have an impact. I'm not sure how they came to a different conclusion.