I'm a psychiatrist and I do not believe Fiona Harvey was lying to Piers Morgan - this is why: Dr MAX PEMBERTON

For the first 20 minutes of her interview with Piers Morgan, I believed every word that 58-year-old Fiona Harvey said.

She was bright, articulate and engaged. She answered all the questions directly and calmly. She held eye contact with Morgan throughout.

Could it really be that the real-life inspiration for ‘Martha’ in the Netflix hit Baby Reindeer was, after all, as innocent as she claimed? Had the damage to her reputation resulting from comedian Richard Gadd’s show been a gross injustice?

After weeks of speculation, Fiona – a woman whose alleged behaviour has brought her the unenviable accolade of the country’s most famous stalker – broke cover. 

On Thursday, her landmark interview with Piers Morgan was broadcast on his Uncensored YouTube show. He says the pre-taped 60-minute exchange has been watched by more than 3.5 million. The Mail, which had chosen not to name her in recent weeks, has now done so.

After weeks of speculation, Fiona Harvey - a woman whose alleged behaviour has brought her the unenviable accolade of the country’s most talked about stalker - broke cover

Piers Morgan with Fiona Harvey, the inspiration for Baby Reindeer's character Martha, who came forward after she said her  portrayal by actress Jessica Gunning was ‘taking over her life’

So why did she do it? Well, in her own words, her astonishing portrayal by actress Jessica Gunning in the show was ‘taking over her life’. She said she had been ‘hounded’ online. This was her chance to set the record straight.

And at least to begin with, her claims to have been wronged by the show’s writer and creator, Richard Gadd, seem entirely convincing. But as the interview went on, the cracks began to appear and her story crumbled piece by piece.

Ms Harvey claimed to possess a photographic memory. So why, for example, could she not recall the class she received for her supposed law degree?

She fast became evasive. Where once there was eye contact, she now looked down to the ground and out around the studio like a fox caught in a trap.

As a psychiatrist, medical ethics rules prevent me from suggesting any kind of diagnosis without speaking to her myself, so I am must be clear that I am not providing one.

Ms Harvey denied stalking Richard Gadd; she denied sending him 41,000 emails, 350 hours of voice messages, 744 tweets, 48 Facebook messages and 106 letters

Fiona's landmark interview with Piers Morgan was viewed by more than 3.5 million people on his Uncensored YouTube show 

But I have frequently worked with patients with the type of ‘delusional disorder’ that Martha (the character which is seemingly based on Harvey) suffers. And the pattern is often the same. Their story begins convincingly, but the longer you engage with them, the clearer it becomes that what they are telling you is a fiction.

I would never describe a patient with delusional disorder as a ‘liar’, though. To them, what they are saying is the absolute truth. ‘Delusional disorder’ is a mental illness which causes the sufferer to believe what they are claiming, even if it has no basis whatsoever in fact. 

I once treated a gentleman who believed he had a worm in his brain. He was so convincing over the course of short assessments with doctors that he managed to have five MRI scans. Anyone who has tried to get such a scan on the NHS knows all too well how tricky getting just one can be.

But when I spoke to this man over an hour or so, his story began to quickly unravel. He claimed his neighbour had broken into his home, placed the worm in his ear and that the creature was now talking to him.

But this patient wasn’t lying. To lie, you have to know you aren’t telling the truth. He believed it absolutely.

There has been online speculation that Martha, the character that seems to be based on Ms Harvey may fall into this category. In her interview with Piers Morgan, Ms Harvey denied stalking Richard Gadd; she denied sending him 41,000 emails, 350 hours of voice messages, 744 tweets, 48 Facebook messages and 106 letters.

She said Gadd’s claims were made up, that he ‘had extreme psychiatric problems’ and that he had ‘done bloody well out of defaming me’. She told Morgan: ‘I find it quite obscene, I find it horrifying, misogynistic.’

But what really worries me about the Baby Reindeer format is the impact all the attention will have on Fiona Harvey herself. 

She is, ultimately, I believe a vulnerable woman who may well have a mental illness and who is being paraded in front of the world like the star of a touring show. 

Netflix drama Baby Reindeer delves into Richard's harrowing real-life stalking ordeal as he plays a fictionalised version of himself called Donny Dunn (pictured)

The Scottish comic played himself in the show while 'Martha' was depicted by Jessica Gunning 

To me, the ethics of providing her with an international platform like Morgan’s YouTube show are distinctly murky.

She claims to have suffered death threats already, after being identified by internet sleuths who are fans of the show. And now that she has identified herself, she may discover that some people are even more unkind in person. 

The paranoia, fear, anxiety and terror this would provoke in any of us would be too much to bear. I am genuinely worried for her.

Fiona Harvey appears to be a prisoner of her own fantasy. It is incredibly dangerous to toy with a woman, who is not used to such public scrutiny and who – by her own admission – has found the attention from Baby Reindeer difficult to cope with.

Yes, the interview made compelling viewing and Morgan conducted it deftly and professionally. But all my long experience of working with mentally unwell people makes me worry about the unintended fallout of putting Harvey under the microscope like this.