What is that "Ford" traffic sign in the UK for?

[Richard_Pearse]

@GIGObuster

In a pit thread there was a post to Warning signs of the road:

http://homepages.cwi.nl/~dik/english/traffic/signs/Aa.html
At the bottom of the page, we have A97a: A worded sign as used in the UK

It consists of the word Ford inside a white triangle with a red edge.

Maybe a warning to Ford Prefects to stay off the road?
What is that sign for?

My educated guess is that it warns of a shallow water crossing in the road ahead.