The Roar of the Butterflies — Reginald Hill

Laid-off lathe operator-turned-private investigator Joe Sixsmith is suddenly very popular, and not just with the ladies. Though he doesn't know a putter from a nine iron, he's being implored to come to the rescue of one Christian Porphyry, the scion of the upper-crust family that owns the most exclusive country club in Luton. Porphyry faces expulsion for the heinous crime of cheating at golf.

Inexplicably, political boss/crime czar "King Rat" Ratcliffe is also interested in employing Joe, offering him some very attractive surveillance work in sunny Spain. But Sixsmith's more intrigued by the first case, especially when a possible witness to the alleged indiscretion mysteriously vanishes.

It's not unusual for Joe to feel out of his depth, but this time he feels out of his class too. Suddenly he faces a potentially fatal pummeling from a variety of sources--and is in grave peril of discovering just how dangerous a contact sport golf can be.