A missing persons expert has shared his major concern as the hunt for missing Jay Slater enters day seven.
The teenager disappeared when attempting to walk back to his accommodation after missing a bus.
He was last heard of when he dialled his friend Lucy Law and said that he needed water and his phone was on one per cent charge.
Speaking to GB News Former Head of Lambeth Missing Persons Unit, Mike Neville revealed his primary concern for the 19-year-old.
Mike Neville shared his worry as they search hit the one week milestone
GB News
He explained: "It has been a long time now and it's an area which is hot in the day and very cold at night.
"Of course, the lad was out in clothes that he'd worn at a festival so a t shirt and shorts. So we can only hope that he is just very, very dehydrated somewhere.
LATEST DEVELOPMENTS
The search for Slater has "intensified" in recent days
PA
"I really feel for the mother, and I know she every mother would have great hope, but it just doesn't look like it at the moment."
He added: "I think the Spanish police have published quite detailed analysis of where they're going to search, focusing on three ravines."
The missing persons expert explained: "This area of Tenerife is is quite wooded. There are so many places that somebody could have laid down to rest or take shelter, and it's not so visible from the air.
"So whilst the Spanish police are making use of helicopters and drones, they're really reliant on humans. Either the police officers, volunteers or park rangers and dogs to try and locate Jay Slater, we can only hope that he is alive and he's okay."
Jay Slater went missing in Tenerife last week
PA
Slater, from Oswaldtwistle, Lancashire, was last heard from on Monday as he told a friend he planned to walk to his accommodation after missing a bus, a journey expected to take around 11 hours on foot.
His friend Lucy said that Slater had gone to stay with people he had met on holiday while on a night out.
She said she received a call from the 19-year-old at around 8.15 am on Monday after he missed the bus and was trying to walk back to warn that he was lost and only had one per cent battery on his phone.
Mountains of Tenerife where Jay Slater disappearedPAHis last location is shown as the Rural de Reno park, a mountainous area popular with hikers.
Yesterday, Slater's mother said that the search had been "stepped up" as Spanish police search for her missing son.
Debbie Duncan told the Guardian she spent eight hours in a police station on Friday as police outlined their detailed plans to search for the missing apprentice bricklayer from Lancashire. “I think it’s been stepped up,” she said, which she described as “too right”.