Two crews (Newport Pagnell, Broughton) alongside an officer attended.
Firefighters were called to two cars involved in a road traffic collision.
One adult sustained serious injuries and was physically trapped inside their vehicle. In a separate car, another adult and a child suffered minor injuries and were also trapped. Firefighters used hydraulic rescue equipment to release all individuals. Once released they were transferred into the care of South Central Ambulance Service.
The incident was then handed over to Thames Valley Police.