WELL, what did you think would happen? Lots of people seemed disappointed by the finale of The Replacement (BBC1, Tuesday) as it all went a bit haywire. Babies were left on windowsills like an apple pie in a fairy tale and then, sticking with the fairy tale theme, a wicked lady spirited the child away, sending its true mother on a quest to rescue her offspring.

But then we veered away from fairy tale and suddenly the story became a thriller: the mother was drugged and left for dead in a sealed car. Would our plucky heroine escape? In real life, no, because she was groggy from some kind of enforced suicide.

The car she was in was locked and its doors were jammed shut with tilted metal cabinets, so even a mother’s primal terror wasn’t enough to surge strength into her drugged body to let her kick in the windscreen.

In real life, there would be no way out but we were no longer anywhere near realism, and even fairy tale land had been left far behind. Now we were in cheap thriller territory and so our nice, middle-class mummy knew how to hotwire a car, triggering the airbags so that a puffy explosion burst through the cracked windscreen.

I’m not a middle-class mother who lives in a stylish mews house, so I can’t comment on how they live their lives, but I thought they went for coffees and yoga classes and blocked the pavements with their gigantic buggies.

However, apparently that’s not all. It seems these women are skilled in the black arts of surviving suicide, prompting explosions and cheating death.

So it’s little wonder that some viewers found the ending a bit daft, but surely we knew to expect this type of thing?

It was all going so well in the first episode, when they plot seemed to be blooming darkly into a subtle, psychological study of female fears.

Maybe, despite being a BBC1 drama, they’d avoid car chases and affairs and murders, and offer something more nuanced?

This was indeed what we were getting until the closing moments of the first episode when a body hurtled through a skylight.

Oh here we go, I huffed. The obligatory dead body, signalling that the hoped-for subtle drama about women being mercilessly pulled in different directions by the demands of career and motherhood is actually just going to point and shout and say “Women, eh? Bunch of psychos!”

The message was that women can’t handle bereavement without tipping towards insanity and murder, and when another woman suspects her of said insanity and murder, everyone thinks she herself is insane. But it’s fine; as long as you can hot-wire a car like Bart Simpson you’ll be able to save everyone!

It’s a shame everything went so awry as I genuinely enjoyed this series, and if the writer had reined in the murders and the madness then it would have been far more powerful. There is strength in subtlety – don’t TV writers know that? Perhaps they do but then some executives come along and insist on it being peppered with violence. It’s prime-time BBC1, you know, so it needs to be spiced up. The writer defanged the script by turning his heroines into Bette Davis and Joan Crawford. Yet our disappointment is perhaps unwarranted, and our expectations too high, because when the dead body came crashing through the roof in the first episode that should’ve been a blaring, shrieking, flashing warning sign not to get our hopes up, and to treat this as just another drama.

But Glasgow looked so beautiful, and the actresses were so steely and fine, and the potential was there for psychological depth, so who can blame us for throwing caution to the wind and expecting more? If we’d only remembered ourselves, and the first episode’s dead body, we’d have found this a satisfying drama, but we’re only human and can’t help but hope for better things.

However, there was some satisfaction to be drawn from the final scene where Ellen and her baby visit Kay’s grave and we see her former boss, David, quietly approach them, hinting that he might now be the “replacement”

for Ellen’s doofus husband who clearly got his psychiatric qualifications via some Nigerian email scam.

So all’s well that ends well, but it could have ended so much better.

AS one drama about murderous, competitive women ended, another began with Big Little Lies (Sky Atlantic, Monday). It is based on a best-selling novel and full of Hollywood stars, two of whom, Reese Witherspoon and Nicole Kidman, tried to get the rights for their individual production companies before agreeing to co-operate on the project.

It seems very promising, but should we fall headfirst into that trap again, or should we be wary? Oh let’s plunge head first!

It’s a commitment to a TV series, not a new house or a marriage. Let’s give our heart to it fully, and trust it not to disappoint. Kidman and Witherspoon play rich, beautiful wives and mothers in the pretty coastal town of Monterey, California. Everyone smiles. Everyone has white teeth and glamorous hair.

Everyone nods hello to their equally beautiful neighbours on the school run.

As the story opens, the first thing we learn is that someone has been killed. A terrible incident occurred at a fundraising party for the school but we don’t know who’s been killed or who did it, and so the story gradually unwinds, being revealed to us via flashbacks and police statements given by the locals.

Some of the witness statements given to the cops are bitchy, suspicious and hostile, showing that the smiley, sunny image of Monterey and its glamorous inhabitants is just a veneer.

We also get a hint of the currents beneath the surface when a new mother moves into town and she’s neither glamorous nor rich.

One of the alpha-mums likens her to a clapped-out banger parked outside a posh boutique.

She doesn’t belong in Monterey, some people are thinking, as are we when we learn she sleeps with a gun under her pillow.

Even the rich and beautiful mothers have their problems. Madeline (Reece Witherspoon) fears she’s losing her teenage daughter to her ex-husband’s new, young wife, and while Celeste (Kidman) has a seemingly perfect marriage, her husband is prone to violent rages.

The show offers us American perfection and just as we’re about to sicken with how sweet it all is, we feel the currents of black water below the surface try to tug us under.

This calm lake of glamour, jealousy, bitchiness and murder is going to be splashed and shaken in the coming weeks.