Police were called at around 1.35am this morning to a report of a parked vehicle on fire outside Pontefract Fire Station on Stumpcross Lane.
The vehicle, which was used to respond to incidents in the local area, was unattended at time and no-one was injured in the incident.
Now officers want to speak to anyone who has information about the arson attack.
Inspector Paul Sullivan, of the Castleford Neighbourhood Policing Team, said : "Following initial enquiries this fire is being treated as arson and investigations are ongoing today.
"The loss of this police vehicle will have an immediate and direct impact on the local community and we do believe the answer to who committed this malicious and utterly stupid act lies in the local Knottingley area.
"We are appealing to anyone who has information or who can assist our investigation to come forwards."
Information can be given to the Knottingley Neighbourhood Policing Team on 101 or anonymously via the independent Crimestoppers charity on 0800 555 111.