CONSIDER your average Victorian photograph; the subjects rarely look like they’re having a laugh, do they?

Man, woman or child, formal studio pose or summer outing, whatever the setting, they all look like they have just been diagnosed with consumption. Or, at the very least, chronic constipation.

Yes, it was a serious old, sepia-hued age of austere mores, dun-coloured clothing and buttoned-up manners, where grown-ups were ancient by 30 and children were seen and not heard, even when, occasionally, they were horribly done away with and stuffed down the privy.

Which was the appalling fate of the poor wee mite who sparked the murder investigation in The Suspicions Of Mr Whicher (Easter Monday, ITV1, 9pm), a one-off period detective drama that was appropriately darker than a widow’s weeds and tenser than a new governess in a randy landowner’s lair.

It was all the more harrowing as it was based on a terrible real-life crime that took place in High Road House, a country pile in Somerset. It shook Victorian society in much the same way as the disappearance of Madeleine McCann shook ours. The victim, three-year-old Savill Kent, was found in the outhouse of the imposing family home.

Enter stage right, the eponymous Mr Whicher, a gifted Met detective (played with a dead-pan authority by Dead Man’s Shoes actor Paddy Considine) who’s dispatched to the sticks to assist the local – and deeply resentful – Wiltshire police with their investigation.

Jack Whicher is generally considered to be the inspiration behind many of our best-loved detectives, including Conan Doyle’s Sherlock Holmes and Inspector Bucket from Dickens’ Bleak House.

And speaking of bleak, Downton Abbey this was not; adding to the oppressive sense of menace was the brooding presence of Savill’s father, Samuel, played by Peter Capaldi, best known for playing Labour spin doctor and swearing machine, Malcolm ‘effing’ Tucker.

Naturally, in this adaptation of Kate Summerscale’s tale, he was not required to curse and swear – but he always looked like he was about to and that trademark hint of something terrible simmering beneath the surface was tangible.

Despite his household being thrown into grief and chaos following his son’s murder and the subsequent investigation and trial, which sees his daughter Constance and son William cited as the main culprits, Kent remains as tight-laced as whalebone corset, something Capaldi relished.

"It’s very interesting as an actor who is so used to being able to express himself by gesticulating manically and swearing outrageously to suddenly play a repressed man who resides in a society where everything is incredibly formal and reserved,” says the 53-year-old Glaswegian actor, who, apparently is a pussy-cat in real life.

It was perfect, if unsettling viewing for a bank holiday weekend and the restrained unfolding of the story, teamed with very fine acting all round, was a joy.

Whicher knew exactly whodunit, yet despite his talent for sniffing out the baddies, he was thwarted by a crucial lack of evidence, i.e. Miss Constance’s missing, blood-soaked nightie.

The machinations of the legal system and the ensuing court room dramas were concisely edited and therefore gripping and you really felt his despair at his inability to nail the murderer.

Fast forward to him wallowing in his rooms, suspended from duty and staring into the bottom of a bottle, when, in a sudden twist of fate, Constance fesses up and he is instantly vindicated.

Even better, the blatantly dodgy local bobby admitted disposing of said nightgown and the rest, as they say, really was history.

Constance shielded her brother, took the wrap, faced trial and was found guilty. She was sentenced to death, but after a public outcry this was changed to 20 years in chokey.

Unlike her poor little step-brother Savill, she lived to be 100.

Whicher ditched the Met and forged a successful career as a private investigator. Surely telly gold gathering interest in the bank, ITV?

PS. There was great excitement at Gibson Towers over the bank holiday when a very old friend popped in. Looking dapper in a fabulous new hat and bubbling over with exciting tales of adventure and derring-do, it was lovely to see him again. I must admit, he did have a few iffy lines in tow, but if you looked away, they soon disappeared, a bit like the monsters. Welcome back Doctor Who.