Claymation type childrens program on british telly sometime in the 80's. Pat is a postman, he delivers the post in his van. He has a black and white cat. There was a theme song to the program but I can't remember it. I can only remember the adulterated version

Postman Pat, Postman Pat
Postman Pat ran over his cat
All the guts were flyying,
Postman Pat was crying
Oh what a very silly man

nine9 informs me that the original song was :

Postman Pat, Postman Pat, 
Postman Pat and His Black and White Cat... 
Early in the morning, 
just as the day is dawning, 
Postman Pat and His Black and White Cat"...