As Boris Johnson steps down as Prime Minister, former Telegraph columnist Tim Walker, author of the soon-to-be-revived play Bloody Difficult Women and writer for the New European, explains why he thinks he “poisoned the well” of journalism.

One of the greatest and most enduring love affairs of my life is in its death throes, and, not for the first time, it’s Boris Johnson who’s the third party and principally to blame. There have been letters, and, just lately, a telephone call, and, quite frankly, I’m devastated.

In the 30 years we’ve been together, I don’t believe I’ve changed at all, but the newspaper industry has, beyond recognition. Cynicism as well as idealism has always been there, of course, but Johnson more or less single-handedly drained it of the latter.