He is noted for the portrayal of himself, or elements of himself, within his novels which usually feature a central character with extensive medical knowledge of drugss and martial arts. This reflects the knowledge Willocks has gained in the practice of martial arts as he has achieved a black belt in Shotokan karate.

Willocks' 1991 novel Bad City Blues was adapted for the screen in 1999 in a movie starring Dennis Hopper. Willocks also wrote the Steven Spielberg documentary The Unfinished Journey.

Willocks wrote the screenplay for the film Swept from the Sea (1997) based on the 1903 novel Amy Foster written by Joseph Conrad.

His most recent novel called The Religion is set in 1565 during the Grand Siege of Malta in 1565 and is the start of a projected trilogy. It centres around the adventures of Mattias Tannhauser a Saxon-born man who, after his family is killed, is trained and becomes a janissary in the army of the Ottoman Empire. After years of service he is repulsed by the ferocious life he lives and he becomes an arms and opium merchant. He is forced to return back from retirement to help the Order of the Hospitaliers against the army of Suleiman the Magnificent and to help one young Maltese countess find her long lost son.

Willocks is rumoured to have had a brief relationship with pop star Madonna. Willocks also is an avid poker fan.

• Bad City Blues (1991)
• Green River Rising (1995)
• Bloodstained Kings (1996)
• Swept from the Sea (1997)
• Amy Foster (1998)

Mattias Tannhauser trilogy

1. The Religion (2006)
2. Twelve Children of Paris (2010)