Here is everything we know so far as the story develops.

We will bring you more as we get it.

What happened?

10-year-old Leah Harrison, a year six pupil at Mount Pleasant school in Darlington, was on an outdoor adventure school trip yesterday just days after she completed her SATS exams.

Just after 1pm, disaster struck whilst the group of children were on a "popular walk" and it is understood that Leah was caught up in the mudslide and tragically passed away.

Emergency services made up of some forty volunteers tried for hours to rescue Leah but it was sadly later confirmed she had passed away.

Leah Harrison. (Image: Terry Blackburn)

Where did it happen?

The mudslide is understood to have happened near Carlton Bank near Carlton In Cleveland whilst the school children were on a "popular walk" route off Cleveland Way.

Conditions were "very wet all day" and "quite foggy and misty" which made conditions difficult for dozens of rescuers who rushed to the scene in a desperate bid to save Leah.

Gary Clarke, callout officer for Cleveland Mountain Rescue, said conditions were “very poor”.

He said: “It was very wet all day, quite foggy and misty up there and very cold and it made the conditions very hard going for the rescue.”

He said 19 rescuers initially turned out, increasing to 30 as the severity of the operation became apparent.

They used a “technical rope rescue system” to recover her body from the dangerous mudslip, Mr Clarke said.

He said the incident happened on a path off the Cleveland Way.

“As far as we are aware, they were part of a school party, where exactly they started and where they were going, we’re not sure, we don’t get to see that side of things,” he said.

“We were acting on behalf of the police service.

“But there was just a school party out for a walk on the North York Moors which many schools do quite often, all year round.

“It’s really a matter for the police investigating now, we’re not exactly sure what happened, but from what we can gather what we saw in that scene, it was just something of a freak force of nature accident.

“It’s something that we’ve never seen or experienced before.”

A general view of Carlton Bank near Carlton-in-Cleveland. (Image: PA)

What has been said?

Tributes have flooded in for young Leah, a budding Lioness from her family and the school.

Her family said on social media: "God only takes the best, please let me tell you he's taken the best there ever was!

"I've been asked to put a message on to thank everyone who has messaged, called and said their condolences it has not gone unnoticed but as a family we are still taking in what has happened to our beautiful Leah.

"Please may we ask for people to give us this time to grieve and come to terms with this news. We all appreciate everything everyone is doing.

"Leah Harrison, the happy bubbly go lucky little girl. The beautiful smile, the giddy laugh the silly jokes.

"You will never ever be forgotten baby girl You will achieve your dream and become a player for the lionesses spread those wings, may you rest in paradise."

Chief Executive of the Lingfield Education Trust, Nick Blackburn has spoken on behalf of the school, paying tribute to Leah and adding that the school community remains in a "state of shock".

Mr Blackburn said: “Leah had her heart set on being a Lioness. She was a really friendly, lovely and bubbly pupil at the school who was well-loved by her friends and the school community.

“We have layers of support here at the school, we have an in-school counsellor who is available for all children today.

“We are also working with a specialist trauma counsellor for some of the pupils who were on the trip.”

What happens now?

It has been confirmed that an investigation has been launched at the council-run site into the incident.

Denise McGuckin, Managing Director of Hartlepool Borough Council, which operates Carlton Adventure said: "We can confirm that a tragic incident occurred during one of the Centre’s instructor-led outdoor education forest walks near Carlton-in-Cleveland yesterday.

"We are utterly devastated and heartbroken and our thoughts are with Leah’s family and friends and all those affected. We are working closely with our partner agencies to carry out a full investigation and we are temporarily suspending all outdoor activities and residential breaks managed by the Council.

"Whilst the investigation is being carried out it would be inappropriate for us to comment further."

Are there plans for tributes?

Leah's family have announced on Facebook that there will be a balloon release in the 'big field' next to Cockerton Park in Darlington on Monday, May 27 at 4pm. 

They have extended the invitation to Leah's friends and anyone else who wishes to pay tribute to the 10-year-old.

Here is a timeline of what has happened so far.