BBC1 series Mrs Wilson is one of the great dramatic gems of 2018, and deserves rather more recognition than it has yet received. In particular, Ruth Wilson should be given a gong for playing her own granny, the eponymous Mrs Wilson, and telling a story that must still cause the family much pain. This immensely addictive three parter (we’re on episode two, wife three and child number five thus far) is based on true, albeit incredible, events.

Bigamy is no laughing matter. Unless you’re the bigamist and you enjoy that sort of thing, which it seems Major Alexander Wilson rather did. Major Wilson (played enigmatically enough by Iain Glen) was the husband of Alison Wilson (actor Ruth’s gran, just to be clear), but Alison was only one of the Major’s many other halves.

The action switches seamlessly back and forth from the weeks after Major Wilson’s sudden death in 1963, to his successive and successful courtships of various women around the time of the Second World War. Major Wilson was, obviously, a considerable con man, though he seems not to have made money out of the unfortunate ladies who orbited him. He seems to have contented himself with impoverishing each of them until his talent as a storyteller (unsurprisingly) led to success as a novelist, and some prosperity, postwar.

Ruth Wilson portrays her granny’s series of traumas with the kind of quiet, polite, bottled-up fury you associate with the wronged English middle classes. So, too, does Keeley Hawes as the latest discovery, Dorothy. She was paired up with the Major initially as part of his cover story for some spy work out in British India, but in due course allowed reality and fiction to merge.

Dorothy was the only one to have known the full truth about the old sod “in real time”, through some skilful stalking, but it didn’t do her much good. She might, though, have done Alison a favour. As Alison points out, Dorothy failed to warn her about him after she spied on the lovers having dinner. The original wife, Gladys (who assumed Alison was his landlady), knew nothing about any of the subsequent “wives”.

With – who knows – yet more women and offspring waiting to tumble out of Major Wilson’s closet, we’re still not much nearer actually understanding why Major Wilson “betrayed Gladys, seduced Dorothy and married me”, as Alison says.

Anyway, the dark blitz blackout scenes are the perfect metaphor for all their fuzzy, shadowy lives. I love the way the eras are so clearly delineated, yet smoothly transitioned, like when Alison looks out of a 1963 window onto a 1942 street below.

Like the gallivanting Major, I confess I can’t wait to meet his next victim.