grammaticality - "Blue colour" or "Colour blue"

Recently I started learning english on busuu.com.

In on of the elementary exercices "Colours", that I performed, the following phrase was stated as the correct answer:

"I like the colour blue"

while my answer "I like the blue colour" was treated as incorrect.

I would appreciate an explanation about a difference that might exist beetween these two phrases.

Thanks.

Answer

I am assuming the question was something along the lines of "What colour do you like?"

The answer "I like the colour blue" means that the colour you like, in general, is blue. The answer "I like the blue colour" implies that there was a given choice of certain colors and you chose the one which is blue (as if you where choosing from colour swatches).

Neither answer is grammatically wrong in itself, but in a given context one option will be correct. In normal conversation people will still understand what you mean, however, simply being understood is not a very high standard and that is likely why your answer was stated as wrong.