An elderly man has been arrested on suspicion of administering poison after several children became ill at a summer camp in England, police said.

After an initial report was made by a third party on Sunday, officers and ambulance workers were deployed to the camp in the village of Stathern, Leicestershire, central England, where the children were assessed.

Eight children were taken to hospital. All have since been discharged and their parents and guardians have been contacted by officers, Leicestershire Police said in a statement.

The arrested 76-year-old man is in custody “on suspicion of administering poison/a noxious thing with intent to injure/aggrieve/annoy,” the force said.

“We understand the concern this incident will have caused to parents, guardians and the surrounding community,” said Detective Inspector Neil Holden, the senior investigating officer.

He added that officers were working with partner agencies, including children’s services, “to ensure full safeguarding is provided to the children involved.”

“This is a complex and sensitive investigation and we will continue to provide updates to both parents and guardians and the public as and when we can,” Holden said.

Local MP Edward Argar told CNN in an email: “The reports of this incident are clearly shocking, and deeply concerning. Our thoughts are with the young people affected, wishing them a full recovery.

“While, understandably, people will have a lot of questions about what has happened, it is important we remember this is a live police criminal investigation, so I would caution against people speculating while the police do that work.”

The East Midlands Special Operations Unit’s Major Incident Team is leading the investigation and anyone with any information is being asked to contact police.

The force has referred itself to the Independent Office for Police Conduct (IOPC) over what it says were the “circumstances of the initial police response” to the incident.

An IOPC spokesperson told CNN: “Our assessment team has examined all available evidence and concluded the matter should be independently investigated by the IOPC.

“The investigation will look at whether there were any breaches of professional behaviour – namely a failure to carry out duties and responsibilities – that resulted in a delay in Leicestershire Police’s response to what was later declared a critical incident.”