There are regular C++ meetups, which I expect would cover systems programming.

It seems however cloud/web people have a different idea of what systems programming is.

Is that ACCU, or someone else now?

ACCU London is not very active anymore, I think CppLondon pretty much took over (it was the same guy as the CppOnSea conference, but I think he started asking other people to arrange it now).

I don't know if it's that great these days, but it's a meetup I used to present at in the past, and I remember having fun getting beers with attendees afterwards.

A decade ago meetup.com was the place to look - if you wanted you could have gone to a different meet up every night, from Linux user group, python testing group, London Java community etc.

It seems like some of these are still active on meetup.com, so that might be a good starting point.

I haven’t been to one yet, but from afar I hear great things about the London Future of Coding meetups.

Been ages for me. Only London one I attended was the perl mongers meet ups but those were drinking based.