Security experts and viewers have been picking apart plot holes and inaccuracies in the BBCs new drama series Nightsleeper.
The six-part thriller starring Peaky Blinders actor Joe Cole features a sleeper train travelling from Motherwell to London which has been hacked and hijacked, or hack-jacked.
The driverless train is seen being operated remotely after a suspect device is attached to wiring within one of the carriages.
But analysts have cast doubt on whether this would be feasible in real life, as they pointed out flaws in the drama created by BAFTA-winning writer Nick Leather.
Like the hit US drama show 24, Nightsleeper unfolds in real time across its six one-hour episodes which are being broadcast on Sunday evenings while they are also already all available on the BBC iPlayer - and it has also been compared to Jed Mercurios hit thriller Bodyguard, from 2018.
New BBC drama series Nightsleeper, starring Peaky Blinders actor Joe Cole (pictured) has received mixed reviews - including criticisms over its plausibility
The six-episode series also features actress Alexandra Roach (pictured) as a security expert
The series created by Nick Leather has divided opinion on X, formerly Twitter
Reviews of Nightsleeper on X, formerly Twitter, have been mixed - ranging from a good old-fashioned romp and a lot of fun to so unrealistic and unbelievable.
Among those enjoying it is Jake Moore, global cybersecurity advisor for tech firm ESET, although he suggested the plot strained credibility.
He told MailOnline: ‘The train is remotely accessed and then sets off by itself - it’s not likely that trains could be operated completely remotely due to the threat level this would entail.
Motives of hackers targeting trains are more likely to cause disruption rail services such as by playing with the signals and operations which are operated remotely rather than making it a danger to life.
But he described the premise as very captivating and interesting, adding: They’re clearly aware of keeping people in suspense.
There is always a threat to national infrastructure and this is a very visual representative of that, using the train network.
The positive comes from really making people more aware of the cyber threats which could potentially pose a risk – it’s a good educational piece.
Meanwhile, another cybersecurity analyst has written two reviews setting out what he describes as the good, the bad and the ugly of the drama.
Alex Cowan, chief executive of RazorSecure which provides security products and services for the rail industry, set out five discrepancies he had noticed.
The six-part thriller starring Joe Cole (pictured) features a sleeper train travelling from Motherwell to London which has been hacked and hijacked, or hack-jacked
Also among the cast is Alex Ferns, who previously played evil character Trevor in EastEnders
Alexandra Roachs character Abby is among those tasked with trying to prevent the train from crashing into a railway station when reaching London
These included apparent misunderstanding of how emergency brakes works, the shutting down of mobile phone signals, lack of attempts to contact a driver, the response of the train crew and how detection software should have been able to notice the suspect device earlier.
He said: This caught everyone in the industry by surprise a couple of weeks ago, with the key questions being "Who consulted on this?" and "How unrealistic will it be?"
I think we all knew the answer to how realistic it would be - spoiler: not very - but no one seemed to know who consulted on it.
He did praise the starting point of the attack, a suspicious device fitted inside a panel in the fictional Heart Of Britain sleeper train.
He said: This hidden Raspberry Pi scenario is realistic - however, the consequences are certainly not. There are significant risks with a rogue device on a train network.
But he quibbled with the unrealistic consequences shown in the drama, including how emergency brakes are not applied when people became aware of the risk.
Mr Cowan said: Theres a fundamental misunderstanding of the emergency brakes in this show. These brakes are managed differently from normal brakes, and very differently from a car.
Firstly, they default to "ON" and must be released to allow the train to move.
For the brakes to be released, the systems must be in a certain state and they must maintain that state. If for example, the train loses power then the brakes will default back to on.
Joe Cole and Alexandra Roach are pictured at a photocall for Nightsleeper on September 9
Cast members Parth Thakerar, Gabriel Howell, Alexandra Roach and Pamela Nomvete are pictured in a scene from the BBC drama
Joe Cole plays an ex-detective who is among the passengers on the hack-jacked sleeper train
He also queried how mobile phone signals on the train were blocked, adding: If no one had phone signal, then how did the device communicate remotely?
And he concluded: Overall the attacks were the most realistic bit of this episode. The consequences and railway elements were not realistic at all, but there are risks attached to these types of attacks.
Fundamentally the way the train crew reacted wasnt so realistic - the train manager would have worked harder to contact the driver if this really happened.
Social media has been busy with viewers commenting on the series, having tuned into the opening episode or binge-watched the entire series.
Among those defending the show was Líam Rudden, who posted posted: ‘The writing might be shonky, the story ridiculously far-fetched, the casting annoyingly uneven but I have to admit, I’m a sucker for a train-bound thriller. #Nightsleeper is a good old-fashioned romp and a lot of fun.’
A user called DeafinitelyHere insisted: I dont get people saying "Oooh, this is so unrealistic", of course it is, thats the whole bloody point!! Sit back and enjoy the ride (no pun intended).
Cal Parrish commented: Just finished binge-watching #Nightsleeper. I did actually really enjoy it. Some ridiculous plot holes and unrealistic stuff but accept it for its absurdism and you should like it!
And Cyber_Hannah_ wrote: ‘Aside from being holy, unrealistic, and laced with clunky dialogue, Nightsleeper was enjoyable. But then again, I am a sucker for hacker storylines.’
But more critical was Rachelbfx3, who wrote: ‘#Nightsleeper definitely peaked in the middle, then becomes unrealistic and slows down. Thanks for the BBCs digs at the state of the UKs train network though.
Social media users have been posting starkly contrasting views of the show
Joe Cole is seen alongside fellow cast members Sharon Smal and Katie Leung
Also featured in the series are (left to right) Alex Ferns, Daniel Cahill and James Cosmo
CretanRunner posted: ‘Episode 1 of Nightsleeper seemed as if the series might be interesting. Episode 2 raised serious doubts. After that it went rapidly downhill. So unrealistic and unbelievable. Try again BBC.’
Martin Hammick remarked: ‘Having seen all of the 6 part BBC series #Nightsleeper, about an electronically hijacked train, its not as bad as some say, but there are flaws in casting, acting, scripting and length.
It shouldve been cut down to five episodes, leaving out most of the comedy+soapy sentimentality.
And Judith Allen stormed: ‘Watching NIGHTSLEEPER and just periodically screaming "this isn’t how any of this works" at the television.
There’s a threshold of inaccuracy that I can accept, when it’s necessary to tell a story and there’s no way around it. And then there’s making s*** up instead of research.