Is it proper to refer to Paul McCartney as "Sir Paul" when he is actually Sir James?

[Spectrum]

According to Wikipedia, musician Paul McCartney of the Beatles was actually born James Paul McCartney, and he was knighted as Sir James Paul McCartney.

Is it proper to refer to him as "Sir Paul"? If we are observing the forms, shouldn't it be "Sir James"?

(I am pretty sure that "Sir McCartney", at least, is not acceptable. The prefix Sir attaches to a given name, not a surname.)

 

[5jj]

The 'Sir' is prefixed in everyday use to the forename by which the person is generally known.

 

[Amigos4]

The 'Sir' is prefixed in everyday use to the forename by which the person is generally known.

The next time I visit the Czech Republic I’ll be sure to ask to see Sir 5jj.

 

[anton_s]

No, it would not be proper to refer to Paul McCartney as "Sir Paul" if his full title is "Sir James Paul McCartney." While "Sir Paul" has become a common nickname for him, it is technically incorrect. The correct way to address him in formal situations would be "Sir James" or "Sir James Paul McCartney."

 

[5jj]

That is not correct, anton.

On extremely formal occasions he might be introduced as Sir James Paul McCartney, but he would not be addressed as "Sir James", and certainly not as "Sir James Paul McCartney."