Born in Inverness; commissioned in the Royal Navy. Author of eight crime and thriller novels included in the Revised Crime Fiction IV; among these, three were novelizations of TV series the author created (Warship) or wrote and produced: Wilde Alliance, and The Sandbaggers, about an elite British Intelligence covert operations unit.

Mackintosh himself died in mysterious fashion. According to a Wikipedia entry, during the third season of The Sandbaggers in July 1979, he and a girlfriend were declared lost at sea after their single-engine aircraft strangely disappeared near Alaska after a radioed call for help.