Cambridge Grammar of English Hardback with cd-rom a comprehensive Guide

Repeated negation and affirmative statements

447c

Two or more negative statements can be used to make a forceful affirmative

statement:

[said by a retired actor who is being asked if his day is now boring and difficult

to fill]

I do

n’t do anything I don’t want to do. 

(more forceful than: I only do things that I want to do.)

[a brand name of a margarine-spread product which claims to taste no different

from butter]

I Ca

n’t Believe It’s Not Butter.

None of the countries have no proper hygiene regulations.

(All of the countries have at least some proper hygiene regulations.)