The possibility of a "successful outcome" in the search for missing teenager Jay Slater is becoming "less and less", journalist Gerard Couzens has warned.

The 19-year-old disappeared on the island of Tenerife last Monday after attending a music festival with friends. Slater had called a friend on Monday morning before his phone battery died, telling her he was going to "walk back to their accommodation" after missing the bus.

Search teams have been scouring the island around the location of Slater's phone before it died, but have been unsuccessful after eight days.

Speaking to GB News, Couzens told hosts Nana Akua and Andrew Pierce that the teams are working with "very difficult terrain" and the "unpredictable behaviour" carried out by Slater before he disappeared.

Couzens explained: "We obviously don't know if after that call he stayed put or he moved on from there - it's very likely he moved on.

"I've just spoken to the police, the search operation is continuing very much in the same way, it has now been going on for a week. But there's lots of places he could fall or have an accident."

Noting Slater's last known movements following his phone call to his friend, Couzens highlighted the "added problems" the police in Spain are facing in this search.

He told GB News: "His behaviour wasn't entirely predictable. He wanted to get a bus back to the south, and yet he was seen walking away from the village in the opposite direction after stopping a neighbour to ask for the bus timetables.

"So that is another added problem for the police."

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Turning the discussion to Slater's friends and family, Andrew highlighted the "trolling" the teenager's mother Debbie Duncan has received and condemned social media users for their actions towards the family following his disappearance.

Andrew fumed: "Is nothing sacred anymore? Why would anybody turn on a mother who's desperately looking for her 19-year-old son, who's been missing for the best part of a week? What is the matter with people?"

Couzens agreed, responding: "It's absolutely awful, these people just need to get a life. She hasn't been up to the scene, because she openly admits she'd find it too upsetting.

"But she's there, and to be receiving this sort of criticism on top of the nightmare she's already enduring, it just beggars belief."

In praise of the Spanish police, Couzens said despite not issuing a public appeal like the British authorities would, they are "quietly working away" and are "focused on the work they're doing".

Couzens added: "It's a very emotionally charged situation, but I think the Spanish police are handling it well, albeit in a very different manner to the way the British police would.

"They're quietly working away in the background and focused, as they told me this morning when I just spoke to them, totally, 100 per cent focused on the work they're doing."