Ask HN: Can I check the connectivity of an ISP without being in its network?

Suppose I want to check whether the Vodafone network in the UK is having an outage or not. I don't have a Vodafone UK subscription, and possibly I'm not even in the UK. Is it possible to check for outage still?

P.S. I don't want to use any third-party service such as Downdetector. I'm looking for a "technical" solution.