UK GSM problems

I work for a company who develops Internet of Things devices. The devices report misc. sensor data using the GSM network. Today, we have not heard from an unusual amount of our devices stationed in the UK. Has anyone heard of general GSM problems in the UK today? I am trying to get hold of our SIM card provider, but they are a bit slow to respond, and I am getting increasingly nervous about the situation. SIM card issue is much more likely than general GSM issues - but I thought it was worth a try to ask hereā€¦

Not heard of anything like that, no.

Not heard of anything like that either. GSM services have been working as usual here today, as far as I know.