"The fact of the matter is, it's easier than you think to go missing."
Those are the words of former undercover detective Peter Bleksley , star of Channel 4 show "Hunted", when asked about the search for fugitive killer Jack Shepherd.
The 30-year-old, who killed his date Charlotte Brown in a speedboat crash in 2015, recently sparked outrage by appealing against his manslaughter conviction - while on the run.
He failed to turn up during his trial and police said there has been "no tangible trace" of him for around five-and-a-half months. Downing Street has even got involved, urging Shepherd to hand himself in.
Despite his apparent ease in evading capture, Mr Bleksley told ITV News that web designer Shepherd "will get caught".
Here, he explains how criminals disappear, why police face a tough task in finding them and identifies the most common mistakes fugitives make while on the run.
How has Jack Shepherd evaded capture?
Mr Bleksley, author of book To Catch A Killer, says "going off-grid" is relatively easy, "if you have the discipline".
"If you can avoid technology and you can sever links with your loved ones, then of course, it's a very big planet in which to disappear," he said.
He said even in a country as small as Britain "it's very manpower-intensive to dedicate police officers to tracking somebody down" and it is likely police don't have "sufficient resources".
"The harsh reality is today, with police numbers being butchered as they have been over recent years, sometimes they just don't have the resources to dedicate officers to searching for someone," he said.
"The UK alone is 74,000 square miles and there's over 60 million people," he says, pointing out that even on his show Hunted, in which 29 experts have 25 days to catch false fugitives, "some still get away".
Even when a suspect fails to appear at court, police often "just don't have the resources to dedicate officers to searching for someone because there's always something else that needs to be done".
Rather than dedicate officers to finding a suspect, "essentially they hope that if you are a law breaker, and you've broken the law once, you'll break the law again, get captured, and it will ping up on the computer that you're wanted in connection with the more historical crimes," Mr Bleksley said.
If Shepherd's contacted his lawyers, why is there no trace of him?
Shepherd's date Charlotte Brown died after he handed her the controls of his shabby speed boat, which the trial heard he'd bought from Gumtree to "pull women".
She subsequently struck a submerged log, which tipped the boat into the icy waters of the Thames and while Shepherd managed to hold on, Ms Brown did not.
Mr Bleksley said it makes him a high-profile target for police.
He believes police "have applied some resources to the search for him because it's a very high profile case, the family are keeping the pressure up on the police, they want something done, as does any right minded individual".
"He's been sentenced to six years in prison, that's where he should be and it's frankly depressing and scandalous that he's not serving the sentence that he should do - somebody died because of his reckless actions."
Police do have the ability to track mobile phones and monitor bank accounts, if the Home Office grants them permission to do so.
Mr Bleksley believes police would have been granted permission "because it's such a high profile case" but he says Shepherd is likely to have taken all the necessary precautions to avoid capture.
"He's ditched any phone that he may previously have used, he's not going to be going to an ATM machine and taking out cash on a regular basis because that would ping up and identify where he is," he said.
In December 2018 Shepherd was given permission to challenge his conviction by a judge at the Court of Appeal and he subsequently contacted his lawyers to mount the challenge.
Mr Bleksley says British police could choose to interview members of Shepherd's legal team but due to "one of the fundamental principles of our criminal justice system, client and lawyer communications are confidential".
He added: "That's only right, as frustrating as it may be, if you're somebody accused of a crime, then of course you should be able to communicate confidentially with your lawyer."
With the relevant permissions police could wire tap his lawyers' phones but Mr Bleksley says it is highly unlikely the Home Secretary would authorise it.
Could Jack Shepherd have escaped abroad?
If an alleged criminal is suspected of fleeing to a foreign country, an international arrest warrant is issued and recognised by international agencies such as Interpol and Europol.
Due to the fact Shepherd’s passport was not seized by the police or the court, as he was on court bail and fully complying with court bail conditions, he could be abroad.
In the case of Shepherd, Mr Bleksley says he suspects international agencies "might be waiting for him to slip up" but "in a perfect world there would be a dedicated team actively looking for him".
Mr Bleksley says even when criminals on the run do make mistakes, their return to face justice is not always inevitable.
He points to the case of alleged murderer Shane O'Brien who, while on the run in Europe, was arrested on suspicion of criminal damage and assault, but Czech police failed to run his fingerprints through databases and he was subsequently released.
The UK has "cooperative arrangements with many, many countries" and Mr Bleksley says mistakes like this shouldn't happen because the National Crime Agency "are very well versed in cooperating with other countries".
If British police wanted to search for Shepherd in other countries themselves, they could only do so with permission from that country.
"You can't go blundering into another sovereign state and start operating without a level of cooperation and permission, because you'd get into trouble, you would upset the establishment of that country," said Mr Bleksley.
Despite examples like O'Brien and Kevin Parle, a Briton linked to two murders who's avoided capture for more than 12 years, Mr Bleksley believes it would be hard for Shepherd to survive as a fugitive in a foreign land.
"It is pretty difficult for somebody to go off into a completely new environment, that they are completely unfamiliar with because, how are they going to communicate, if there's a foreign language being spoken, how is he going to get money and how will he be funded?" Mr Bleksley said.
"I would be looking at his known associates that might be willing to support him or fund him, somebody is going to be helping him."
He says Shepherd, who lived on a houseboat in Hammersmith in London before his conviction, doesn't strike him "as the kind of character who is going to suffer any discomfort, I suspect he probably enjoys the creature comforts, I don't suspect that he is living rough, so to speak."
So where can the investigation go from here?
At this stage Mr Bleksley says the best tool police now have to find Shepherd is public appeals.
"So often it's the public that have that vital piece of information that will lead to that phone call being made and in turn will lead to an arrest," he said.
"The harsh reality is there are so many demands on our police these days, that I'm a bit sceptical as to how many police officers today are actually physically searching for him - not very many I would suggest."
He added: "Jack Shepherd is going to be incapable of being on the run for the rest of his life, because when you live your life looking over your shoulder, each and every day, it is very, very draining both mentally and physically, you're always living in fear of that knock on the door.
"He will commit another crime, or he will reach out to somebody known to the police, who they are monitoring, or - the pressure becomes so unbearable - that he sees his face splashed across the media and on wanted posters and the pressure of life on the run becomes so unbearable that he hands himself in."
Detective Chief Inspector Mick Norman, from the Metropolitan Police, confirmed the investigation was ongoing in a statement issued at the start of 2019.
"The Met continue to work closely with the Crown Prosecution Service and also the National Crime Agency to track, trace and arrest Shepherd wherever he is in the world," he said.
"We would also appeal to Mr Shepherd’s friends and associates who may be assisting him through a misplaced sense of loyalty to do the right thing and share any information they have with the police."