Back in the early 1960s (when I'm guessing this photo was taken) Austin was making vehicles for all four of the emergency services - police cars, fire engines, ambulances and brewery drays.
The caption on the back of this photograph reads "Austin 25cwt used by Ansells Brewery for emergency deliveries".
I can't believe how trusting they were back then. Can you imagine delivering beer in an open truck today? It would more than likely be empty by the time it reached its destination.