A police car responding to an accident in London this week made matters worse when it caught fire and the flames spread to a vehicle it had come to assist.

The cause of the blaze is unknown, but a mechanical fault is suspected.

"The police vehicle, a marked BMW 5 Series, will be examined by the Met's Fleet Services to determine exactly what caused the issue," a Metropolitan Police Service spokesman said.

Before and after photos from the Tuesday incident indicate that the fire started in the engine compartment of the station wagon.

BMW recently issued a massive recall for several models due to fire risk, although it is not clear if this was one of the affected cars.

No one was injured by the inferno, according to SWNS, but victims of the original accident were taken to the hospital with non-life-threatening injuries.