Which of his own songs did robbie Williams not write?

Robbie Williams has co-written the majority of his songs, so there is no one definitive answer to this question. However, some songs that Williams did not write include:

Rock DJ (1997)

Millennium (1998)

She's the One (1998)

Supreme (1998)

Let Me Entertain You (1998)

No Regrets (1998)

Strong (1999)