Most billing has been outsourced since the early 2000s at least. One large Dutch mobile provider has handed over most of their technical staff to Huawei. At one major mobile provider the chain is now that the company has outsourced IT to Tech Mahindra. In turn, the company in turn talks to Ericsson, who then finally operate the network.
The idea that telecommunication service providers can guarantee the privacy of their subscribers is highly questionable. All service providers have a security department, and I know many of these people well, and feel their pain. Sadly in all providers I know, security departments struggle to get their recommendations implemented.
Ericsson software components appear to be developed in China, which may bring worries of its own. European service providers have reasons beyond balance-sheet gymnastics to outsource. All large scale outsourcing companies have been thoroughly compromised. In the end, outsourcing is now almost the only possibility to survive. One European 15-million subscriber network now relies on a core team of 4 people (one of whom is their manager) Technical expertise is the first line of defense against malicious vendors attempting to spy and destabilise. Having strong local knowledge of telecommunications helps assure the future autonomy of vital capabilities. European service providers are by and large currently not in good control of their networks, writes Picking Huawei is not specifically a sea change but simply a continuation of existing policy for most providers. If we really care about our privacy and the stability of our communication networks, we should be able to build such networks autonomously. The Galmon GNSS Monitoring Project monitors the RNA levels of humans in the human genome.