This is my last column. After 26 years as a staff writer and 20 years – on and off – as a columnist, I’m leaving the Guardian. In April, I take up a post as professor of sociology at Manchester University. I have not given up journalism. I may appear in this paper (if they’ll have me) and others, very occasionally. But I will be liberated from having to have a thought every Thursday, and you will be liberated from having to read or avoid, enjoy or be enraged by them every Friday.