Youth held following attack on girl of 10

He was detained after the girl, from Stockton-on-Tees, was found with head injuries.

She was taken to a specialist paediatric unit in Newcastle, where her injuries were deemed to be “serious but not life-threatening”.

Cleveland Police said more than 40 police officers and civilian staff were working “round the clock” to try to establish what happened.

The alarm was raised at 6.30pm on Saturday when the girl went missing from her home.

She was found in Maritime Way, Stockton, at 9pm by a member of the public.

A police spokeswoman said the girl was taken to the Royal Victoria Infirmary, in Newcastle, where she remained last night.

The spokeswoman said: “Initial inquiries suggest she had been the victim of a serious assault.”

The 16-year-old was arrested at noon yesterday in connection with the incident.

The spokeswoman said the operation involved specially trained search staff, as well as detectives, neighbourhood police teams and a helicopter.

An incident room has been set up with 48 staff dedicated to the investigation, she said.

The girl is 4ft and has brown hair.

She was wearing black leggings and a chequered top, with a brown, furry body-warmer when she went missing.

Police said they wanted to hear from anyone who saw a girl matching that description “either alone or with someone else” between 5pm and 9pm on Saturday.

The spokeswoman said the team had been “working round the clock to establish who she was with and where she had been throughout the evening”.

She added: “Police are asking the local community to work with them and remain calm.”

Neighbourhood police patrols have been stepped up in the area to reassure residents.

Anyone with information about the incident should contact the incident room on 01642 302390 or 01642 302388.

Witnesses can also call Crimestoppers anonymously on 0800 555 111.