The little girl's plight was enough to melt the hardest of hearts. Four-year-old Bru Ahmadi was living with her father in that squalid refugee camp near Calais known as The Jungle.

Home was a small tent made of plastic sheeting draped over a rope strung between two trees. When it rained, the water found its way through gaps in the awning and drenched their pillows and blankets.

The only way to stay warm was to add another layer of clothes and hope the next day dawned warmer and drier.

Despite the appalling conditions, with her dark eyes, jet-black hair and impish grin, Bru charmed everyone who met her. And one of the camp volunteers who fell under her spell was an eccentric English ex-soldier in a pink Stetson called Rob Lawrie.

Her father Reza told him that they had fled rural Afghanistan after the Taliban killed his wife and threatened his own life.

The little girl's plight was enough to melt the hardest of hearts. Four-year-old Bru Ahmadi (pictured) was living with her father in that squalid refugee camp near Calais known as The Jungle

Having endured perils and privations crossing two continents, the pair arrived at The Jungle and all Reza wanted now was for someone to take Bru across the Channel so the little girl could have a better life in the UK.

Mr Lawrie turned out to be the guardian angel he was looking for.

But while he was well meaning, he was also naive. His failed attempt to smuggle the little girl became a cause celebre; an example of personal sacrifice for a good cause. And what a sacrifice: his good name, his marriage, his business, almost his freedom.

But now, four years later, Mr Lawrie has found out that very little of Bru's heartbreaking story was true.

This 'staggering' discovery comes thanks to a piece of journalistic detective work which is now the subject of a gripping BBC podcast.

It tells the story of an extraordinary betrayal of trust on Mr Ahmadi's part — not once but twice — and with catastrophic consequences for the adults he duped along the way.

We must also consider two other younger victims who — for the moment, at least — remain unaware of the nature and the depth of the wrong done to them. One of them, of course, is Bru. The other is her little sister whom her father abandoned and whose existence he denied.

Having endured perils and privations crossing two continents, the pair arrived at The Jungle and all Reza (pictured) wanted now was for someone to take Bru across the Channel so the little girl could have a better life in the UK

Mr Lawrie's part in this saga dates back to September 2015 when he, like many, was shocked by pictures of the body of the three-year-old Syrian child Alan Kurdi.

He had been washed up on the shore of the Mediterranean after his family's disastrous attempt to cross from Turkey to Greece.

Mr Lawrie was married with two children and owned his own carpet-cleaning business near Leeds. But he had spent some of his youth in a children's home and was deeply affected by this image of infant vulnerability.

He felt he had to do something to help others like Alan. He resolved to use money he had won on the television game show Deal Or No Deal to do so.

Packing his company van, he set off for The Jungle. Wearing his trademark lucky Stetson which he had worn on the game show, Mr Lawrie was to visit the chaotic and dangerous camp — then home to some 6,000 migrants from 25 countries — on a number of occasions.

He helped build better accommodation for its refugees and on one such visit met Reza and Bru Ahmadi, then aged four.

The story Reza told the credulous Englishman was heart-breaking. The Taliban had forced him off his land and his wife was probably dead.

A baby son was being cared for by relatives.

Mr Lawrie could see with his own eyes that their current circumstances were little better.

The Ahmadis lived in a small tent which leaked. There was no electricity.

It did not take much for the Afghan to persuade Mr Lawrie to smuggle them both to England. He said he had distant relatives in Yorkshire who would help them on arrival.

Despite the appalling conditions, with her dark eyes, jet-black hair and impish grin, Bru charmed everyone who met her. And one of the camp volunteers who fell under her spell was an eccentric English ex-soldier in a pink Stetson called Rob Lawrie (pictured)

But, when the night of the attempt came, it was found there was not enough room for father and daughter to hide in the sleeping compartment above the cab of Mr Lawrie's van.

Reza argued that the Englishman should take Bru anyway. He would pay people-smugglers to find him another way later.

His relatives in the UK would contact Mr Lawrie and collect Bru.

Foolishly you might think, the Englishman agreed. Almost immediately, the plan went wrong. Unbeknown to Mr Lawrie, two Eritrean migrants had hidden themselves in the back of his van and they were detected by police sniffer dogs.

Mr Lawrie then told the police about Bru. He was placed under arrest and told he faced people-smuggling charges which carried a maximum five-year prison sentence and a 30,000 euro fine.

The court case attracted widespread publicity. To his credit, Reza Ahmadi appeared to plead the Englishman's case.

Mr Lawrie was eventually cleared of people-smuggling and given a suspended fine for allowing Bru to travel without a seat-belt.

But it wasn't just the rash plan which had unravelled. By then, so had Mr Lawrie's life.

Unaware of the risks he had been running, his furious wife left him and his business suffered.

Meanwhile, Reza and Bru remained in The Jungle. Their 'saviour' had lost everything for nothing. Or not quite everything. A Hollywood film director had got in touch with him after his arrest. He was interested, he said, in turning the relationship between the Afghan refugee and the English Good Samaritan into a movie.

Mr Lawrie wondered whether money made by the film could be used to help Reza and Bru. But they had dropped out of contact after The Jungle was demolished in late 2016. Reza's mobile phone was dead.

Then this strange story took another unexpected twist.

BBC journalist Sue Mitchell had been present in court for Mr Lawrie's hearing. Afterwards, they stayed in touch. When she was visiting Mr Lawrie's home he received an email which would turn their understanding of events on its head.

The email was from a volunteer working with refugees in Denmark. He said he had met a woman called Goli who claimed to be Bru's mother and Reza's wife.

She was not dead but desperately searching for her daughter.

The woman called Goli had made other bombshell claims.

Reza had not fled Afghanistan as a refugee from the Taliban. He had moved to Iran as a child and had been living with Goli, Bru and their new-born daughter Baran in a rented flat in the capital Tehran. There was no baby son.

Then, without warning, he disappeared with Bru, then aged three. Not because his life was under threat; he abandoned Goli and Baran simply because he wanted a different, better living in the UK. Relatives already there had done well financially.

Mitchell went to Denmark and found Goli. She told her visitor that Reza had been 'furious' when she got pregnant for the second time.

After he left, she was forced to stay with his family. He contacted her only once, to say he was in Turkey with Bru.

'I said to Reza, 'Just come back with Bru. Don't destroy everything',' Goli told Mitchell. 'He said, 'I can't have that life in Iran. I just want to go and settle somewhere.' He said he had brought Bru to make it easier for him to get asylum.'

Her husband promised her that once he got asylum in the West he would send for her and the baby.

In the meantime, she lived a miserable existence with no status among the family of the man who had betrayed her.

Eventually, Goli decided she and her younger daughter must follow him to Europe to find Bru. She mostly travelled by foot before crossing the Aegean in a smuggler's dinghy. The boat capsized and she almost lost Baran.

Their journey eventually took them to Denmark where they stopped because Baran was sick. They were given a place at an asylum centre and it was there that a translator recognised a picture of Bru on the BBC website.

So where were Reza and Bru?

At first, the Red Cross confirmed that they were still in Calais. Then came a letter from the organisation saying that father and daughter were thought to have crossed illegally to the UK, whereabouts unknown.

The search for them began on social media. Mr Lawrie posted a message on Facebook in which he mentioned the possible Hollywood movie and the money it could make him.

Reza took the bait. Mr Lawrie first received a response from someone claiming to be a relative of the Afghan, asking about the money. Then came an anonymous text, to which Mr Lawrie replied, saying that he would give half of the film's proceeds to Bru. Eventually Reza texted 'We must talk'.

But he was suspicious. He claimed he was not in the UK. Then that he did not need help. Bru remained out of reach still.

Weeks passed before Reza got back in contact. He wanted to meet at a shopping centre in Scotland. The meeting, between Mr Lawrie and Reza eventually took place at a branch of Starbucks.

The Afghan was nervous but greeted the Englishman with a smile. And there, with him, was Bru, by then aged seven. She spoke good English and seemed happy.

Reza admitted that he 'cut a limited story' to immigration officials — presumably the same nonsense he had told Mr Lawrie. But they had granted them both the legal right to remain in the UK.

Afterwards, Mitchell sent photographs she had taken of Bru to Goli in Denmark, who was overwhelmed. But still they did not know where the little girl and her father were living.

Reza remained very suspicious, but agreed to another meeting. It took place last December. This time Mr Lawrie gave him a teddy bear to give to Bru. What Reza did not know was that secreted inside the soft toy was a tracking device linked to an app.

Reza took it. And it led the searchers to a nearby block of flats. Further evidence confirmed that father and daughter were resident. Bru, now eight, had been found.

But what to do next? She had spent more than half her life alone with her father.

Her mother only had refugee status in Denmark.

The Home Office is now investigating Reza Ahmadi's asylum status. He seems to have told a number of people a large number of untruths with hard consequences for all.

The future is unclear.

Goli, Bru and Baran were finally, briefly, reunited after an SNP MP arranged for Goli and Baran — who had refugee status in Denmark — to fly to the UK before Christmas.

While the two little girls embraced joyfully, it was a bittersweet experience for Goli. After the meeting she told Mitchell: 'Bru was totally unprepared. She doesn't have any background of her mother. She thinks, 'My mother is not alive and I don't have any mother'.

'She tried to come close to me. It was incredible to see her for the first time.

'I can see how much she's grown up, how beautiful she is, how independent she is and so I don't feel too sad. I can forgive something.'

And Mr Lawrie?

He can forgive Reza Ahmadi — now. But learning the truth has been hard.

In fact, he said, 'I feel like I've been hit round the back of the head with a cricket bat, it's just staggering.'