The problem with trying to cram the gruesome life of a prolific murderer into two neat television episodes is there simply isn’t enough time.

ITV’s Dark Angel seemed like a promising drama. The true story of Britain’s first female serial killer Mary Ann Cotton who ploughed her way through as many as 21 victims. Intriguing. I was looking forward to it.

But it swiftly became all too clear that this 19th century saga of horror had been turned into a rapid race to the finish. As Mary dispensed her lethal arsenic tea and her various husbands and children bit the dust it was hard to keep up.

They were dropping like flies. One of her unfortunate spouses lasted about five minutes. Scene one: they meet in hospital where he’s a patient and she’s a nurse. Scene two: They’re at the altar getting married. Scene three: he’s getting buried.

When she’s not snuffing out her nearest and dearest our deadly heroine is busy bonking her bit on the side Joe, who thinks he’s really good at sex but isn’t. He shags like a shunter train. Quite why Mary is so irresistibly drawn to a scruffy oaf who shoves her against the pier and rams it in remains a mystery.

Played by Downton Abbey actress Joanne Froggatt, Mary’s strong Northumberland accent sounds a bit like that announcer guy on Big Brother. Actually, she’d do well as a modern-day TV star. Maybe one half of a popular double act… Ant & Death.

Anyway, almost by accident, Mrs Murderess discovers the wonder of life insurance. After her dad helps her take out a policy on husband number one, his poison-induced demise nets her 35 quid. A lot of money in those days. The first kid to croak brings in another two pounds and ten shillings. She’s in business.

When Mary’s mother clocks that her dreadful daughter slaughters for cash, she fears for her latest betrothed. “Got life insurance on this new one?” she sarcastically enquires. Mary: “Let me make you a nice cup of tea.” Cut to the graveyard. Mum’s a goner.

Back then the police were only just getting started. They were even worse than they are today. So the constant tragedies that came along like clockwork in Mary’s implausibly turbulent life failed to ring any alarm bells. Even the insurance companies just coughed up no questions asked.

Now she’s moving up in the world, having set her sinister sights on well-to-do widower Mr Robinson. “I shall be Mrs Robinson,” she vows. Here’s to you Mrs Robinson, Jesus loves you less than you will know. Look out, Mr R… you’re in deep trouble.

So that’s it for a frantic opening salvo. Tune in next week for another fast-track journey into the dark heart of the Dark Angel. And don’t blink… or you’ll miss another homicide.

The entire cast are fighting a losing battling with a hectic script that doesn’t have time to breath. This should have been a proper series, not a two part rocket trip. But decent performances by Ms Froggatt and the ever-reliable Alun Armstrong as her long-suffering father. With his Dickensian features, Alun has a face right out of history.

“I’ve done some terrible things,” Mary confesses to her doting dad. To which he replies: “We’ve all done daft things.” Poor bloke. Sometimes it’s hard to be a parent.