Unflappable. Humane. A presenter who “purrs along with superb engineering”. That’s how Justin Webb’s colleagues at the Today programme describe him. In an age of shouty politics, the 61-year-old calmly goes about the business of sifting sense from a revolving cast of evasive and borderline-delusional interviewees. Listeners may have found themselves wondering how he keeps his head while all about him are losing theirs. The explanation? He’s being practising since childhood.

In this crisp, un-self-pitying memoir, Webb reveals that he was raised in a household dominated by madness. His stepfather, Charles, was a paranoiac who heard voices and blasted Bach out into their terraced street in the middle of the night. His mother, Gloria, was a tangle of contradictions who wanted her son to skip school and learn to smoke. She was a snob who ruthlessly mocked those who said “perfume” not “scent”, but also embraced Maoism. With such an unreliable husband, Gloria looked to her only child to become the voice of smart, smooth stability.

With thoughtful concision, Webb works out how this “wan” nuclear family came to be. He explains that Gloria Crocombe was born in 1924 and raised in comfort in Walton-on-Thames. Her father was a “big noise in magazines” and a friend of Lord Reith. He employed a cook, a maid and a driver to take the family for picnics on the Sussex Downs and wait in the car while they ate.

But the war whipped the cushions out from under Gloria’s youth. Funds were tightened and servants lost. Her dad left the family and took his remaining money with him. Although she was clever, university wasn’t an option for most girls. The pool of men available was shallow, the pickings often shellshocked. “Yes, there were balls and there was booze,” writes Webb. “There was a large army into which my Uncle Oliver subsided via Sandhurst. But there was, too, a general reduction in life chances.”

Gloria married “an alcoholic with a tin leg” and settled, briefly, in the Home Counties. There was a divorce and a series of romances that her son says “ended poorly”. Her most significant romance with a man who took her on a thrilling holiday to France, then began vomiting blood as they returned to England. After he died, Gloria worked for a spell as a newsroom secretary at the Daily Mirror. There she had an affair with the paper’s married star reporter, Peter Woods. That ended when she became pregnant with Justin.