The Au Pair on Channel 5 has divided viewers with some calling it "farcical" and "predictable", while others enjoyed it so much they've binged the lot on My5 - but one thing they're united on is the rather glaring plot holes in the script.

The four-part series introduced the Dalton family, who seemed to be living a perfectly happy life until the arrival of an au pair. Like the famous 1992 film The Hand That Rocks the Cradle, everything started to go horribly wrong after the live-in nanny got her foot inside the door.

The original Channel 5 thriller had a pretty impressive task, including David Suchet in his first screen role for seven years... But even the mighty Suchet - famous for playing Agatha Christie's detective Hercule Poirot - wasn't able to solve some of the show's biggest bloopers.

Here's the five biggest plot holes viewers have flagged as huge mistakes in The Au Pair...

***Warning: spoilers from The Au Pair ahead***

Major plot holes in The Au Pair on Channel 5: How did Sandrine get hired?

In episode 1 of The Au Pair, French Sandrine discovered the Daltons were looking for a nanny, and inserted herself in their lives - having first intercepted a potential 'real' au pair arriving at the house and telling her the job had gone.

A Channel 5 synopsis told us: "Zoe reluctantly agrees to hire an au pair... In comes Sandrine, a beguiling young French woman, who triggers an unsettling shift in the household. Instincts and suspicions arise as hidden agendas and long-concealed truths bubble to the surface..."

But, viewers quickly found a pretty big flaw straight away. Namely, how on earth did Sandrine (Ludmilla Makowski) get hired in the first place?!

One baffled viewer posted on X, formerly known as Twitter: "It's great to know you can still get a job with kids without having any background checks or your passport looked at."

Another stated: "You'd have to be DBS checked to be an au pair."

A third added: "Do any of these people do background checks?"

I mean, if you're going to hire the first person to turn up on your doorstep, perhaps you deserve everything you get?

Why did no one notice Sandrine was the cause of all the problems?

Another huge complaint that viewers had during The Au Pair was how naive (I'm being kind here) Zoe, Chris and George seemed to be...

First of all, a new au pair arrived in the house, and then everything started going wrong. But instead of pointing the finger at the newcomer, they turned on each other!

One viewer fumed: "It's utterly ridiculous how none of them notice all this weird stuff only started happening after Sandrine arrived, and they trust her so much after knowing her five minutes."

Another added: "What gets me with these kind of plots is that they just can't make the connections that all these things start happening since the arrival of the au pair!"

A third wrote: "I was looking forward to this, but it seems to be going along the same old usual storyline. Why do people not just see what's happening under their noses??"

Another said: "This storyline is getting crazy. How is Sandrine getting away with this? Why are these people so thick?"

"Why was nobody noticing all those things happening as soon as the au pair arrived, especially that dress?" lamented another, while one more said: "Why would the husband even be listening to the au pair, considering she's only been there five minutes?"

Viewers also called out the moment Sandrine kicked Zoe's stool, causing her to fall to the ground. Once again, Zoe did not realise that her au pair had done it. Others questioned why Sandrine didn't let Zoe drown in the bath after drugging her, and why no one noticed that the tapestry caught fire when it was nowhere near any flames!

Sandrine attacked Amber and hid the body

During episode 2 of The Au Pair, Amber's birthday party came to a rather dramatic head. In fact, anything that could have gone wrong, did.

Not only did Amber's beautiful tapestry from Zoe catch light, thanks to Sandrine, Zoe was pushed off a stool leaving her fearing for her unborn baby's life. Also, thanks to Sandrine.

But the climax moment was when Amber discovered the truth about Sandrine's identity and threatened to expose her. Sandrine hit Amber over the head with a chopping board (yes, really), knocking her out in the process.

There followed a rather "comical" scene in which Sandrine tried to get Amber's lifeless body out of the house... But she wasn't exactly discreet.

One bemused viewer wrote: "I found that rather comical when 'Sandrine' dragged an unconscious Amber into the greenhouse, and then bundled her into a cross between a wheelbarrow and a tricycle, donned a hoodie and peddled away from a house/garden where there were lots of people UNNOTICED. Seriously!! All those people there and nobody sees her doing any of this stuff."

Another added: "Did I just see.… #TheAuPair peddling along with the daughter's legs hanging out of the box at the front??"

A third wrote: "Now she's taking the body on a bike with her legs hanging out. Fawlty Towers springs to mind."

One more said: "Birthday girl being dragged into the garden by the ankles and no one notices… FFS."

The Au Pair plot holes: Sleeping tablets and medication

Sandrine didn't stop at hurting Zoe and Amber either. The au pair also targeted Zoe's poorly dad George, who lived next door. A diabetic, he relied on regular medication to keep him healthy. However, viewers were quick to notice that his meds were wrong.

One wrote: "Quite early on noted a blooper! George was said to have 'dangerously low blood sugar levels', so what did they do? Gave him insulin, d'oh!!! That would have made his sugars lower not helped!!"

Another noticed too, adding: "Did they just give insulin to a bloke with low blood sugar, who then wakes up immediately? Who wrote this rubbish? #TheAuPair."

Other criticised the scene where Sandrine drugged George with sleeping tablets, which seemed to take hold incredibly quickly!

One viewer wrote: "Did he take an hour to eat that soup! Sleeping tablets wouldn't work that quick. He barely swallowed that spoonful."

Another said: "How fast did those sleeping tablets work?!"

A third believed the pills would have tasted unpleasant, typing: "Such a common mistake in TV dramas: if you grind down pills such as sleeping tablets and put them in food or drink, the person eating/drinking it would notice straight away as there would be a very bitter taste."

Especially a doctor like George!

Lastly, one baffled viewer wondered why George would "be trying to climb stairs if feeling so poorly?"

Pregnant Zoe's baby scan

After Sandrine booted Zoe's stool from under her feet during Amber's party, Zoe was worried the fall had damaged her unborn baby.

Accepting help from the very person who had put her in danger, Zoe and Sandrine headed to the hospital to get Zoe checked out.

And viewers found some more obvious plot holes.

One viewer said: "That's a pretty well developed five-week-old foetus."

While another added: "I'm not sure which NHS hospital she went to with a quick 10 mins in and out."

Luckily, the baby was fine, and Zoe was able to return to the party without anyone really noticing she'd gone...

And The Au Pair ending? Did anyone see THAT coming? Nope, me neither! But that's a whole other article...

Read more: The Au Pair on Channel 5: Five best bingeworthy thrillers on My5 if you enjoyed the Sally Bretton series

The Au Pair is currently available to watch on My5.