usage of 'never again'

Is it mandatory that 'never again' is not separated in a sentence?

Do I have to write "I will never again do anything like that." or may I also put it "I will never do anything like that again."?

If you may separate the two words, is there a rule when to separate them?

Solution 1:

Whether you write the words never again together or at a remove from each is a matter of style not grammar. In my view, writing them together gives the phrase slightly more emphasis, but others may have a different opinion.

There is one circumstance, however, when they most usually stay together, namely at the beginning of a clause, followed by an inversion of subject and verb:

• Never again will I listen to what you say.
• Never again will he speak to me like that.

Fronting the expression in this way gives it even greater emphasis.