A HEADTEACHER has led the tributes to a "bright and wonderful" 13-year-old who died suddenly in unexplained circumstances.

Emergency services were called on Monday evening to Mason Douglass' home in Acklam, Middlesbrough, after reports that the youngster had gone into cardiac arrest.

The Great North Air Ambulance landed at Acklam Whin Primary School, near Trimdon Avenue, at about 5.40pm.

The on-board doctor treated the youngster at a house on nearby Bank Sands, then accompanied him to James Cook University Hospital by road ambulance.

Andrea Crawshaw, headteacher of Acklam Grange School, led the tributes to Mason.

"One of our students, Mason Douglass in Year 9, passed away last night," she said.

"Mason was an excellent, bright, wonderful young man who is a credit to Acklam Grange School.

"Our thoughts and prayers are with Mason's family and friends at this difficult time."

She said students and staff were being supported in school, through the school's pastoral care system, and were also receiving help and advice from trained bereavement counsellors.

Mason was a former student leader and his teacher described him as a "great ambassador" for his year group and school.

Cleveland Police said investigations were still at an early stage, and that the youngster's family were being supported by police.

The death is still being treated as unexplained with a post mortem examination due to take place on Wednesday.

Some people on social media suggested that there had been a dog attack, but a spokeswoman for Cleveland Police said this was "definitely not" the case.

Tributes poured on on Facebook, with people speaking highly of Mason.

Wendy James said: "You were an adorable man, always smiling and always made me laugh. I can't believe it. I'm heartbroken so I can't imagine how you all feel."

Another friend said he would be "sorely missed by not just people who knew you but the whole community."