Filming in Glasgow
There were police standing at the end of the street and a crowd gathered. Fortunately, it turned out they were just filming something.
I’ve no idea what but it looked vaguely 28 days later-ish since there were all sorts of posters up for many different missing people and burnt out cars etc.
[Edit] a quick search on Twitter reveals it to be the set of Ewan McGregors next film The Last Word.