What type hat and what brand is it that Brad Pitt wearing in Snatch?

Brad Pitt's character, "One Punch" Mickey O'Neil, in the movie Snatch wears a flat cap or newsboy cap. It's not explicitly stated what brand it is, but it's likely a generic, unbranded type.

These caps were very popular among working-class men in the UK during the time period the movie is set in (the late 1990s).

While we can't pinpoint the exact brand, the cap's design and style are common features of flat caps, making it easy to find similar options from various brands today.