For the conspiracy theorists O2 is currently suffering a massive mobile network outage in the UK [https://www.telegraph.co.uk/technology/2018/12/06/o2-network...]. Apparently it has been caused by a third party supplier [https://twitter.com/O2/status/1070612301110226944]. Apparently, O2 uses Huawei [http://telecoms.com/44197/huawei-wins-managed-services-deal-...] but has recently been boasting about moving away from them [can't find a reference].

But someone on twitter is claiming the third party is not Huawei. [https://twitter.com/NicFildes/status/1070606845881008128]