Three people are in hospital after a suspected carbon monoxide leak at a school in Stevenage this afternoon (June 12).

Police, fire and ambulance crews were called to Martins Wood Primary School in Mildmay Road just after 1pm, following reports of a number of children and adults becoming unwell.

One adult and two children have been taken to Lister Hospital by ambulance with suspected carbon monoxide poisoning, while a further six adults and nine children were assessed at the scene.

The gas leak is believed to be an isolated one, with Hertfordshire Fire and Rescue carrying out an investigation.

"We were called just after 1pm today (June 12) to Martins Wood Primary School in Mildmay Road in Stevenage. This followed reports of a number of children and adults becoming unwell due to a suspected carbon monoxide leak," said an East of England Ambulance Service spokesperson.

Police at the scene in Mildmay Road.Police at the scene in Mildmay Road. (Image: Georgia Barrow)

"A total of 15 patients were assessed at the scene – six adults and nine children. One adult and two children have been taken to the Lister Hospital by ambulance for further assessment.

"We have given advice to parents on what they should do if their child feels unwell later. If parents have any concerns about their children’s condition following today’s incident, please call 111.

"Hertfordshire Fire and Rescue are carrying out checks on the site but believe they have isolated the fault."

Martins Wood Primary School provided an update on their Facebook page, confirming that children had left the building following the suspected leak.

Mildmay Road and Derby Way were both closed during the incident but have now reopened.

A Herts police spokesperson told The Comet: "Police were called  to assist the East of England Ambulance Service and the Hertfordshire Fire and Rescue Service with an incident in Mildmay Road, Stevenage."