Matt Ritchie scored for the youthful looking Pompey Reserves but goals from Zavon Hines, Freddie Sears and Lee Hales from West Ham gave the second-bottom side the three points.
This defeat adds more humiliation to the Reserve side who have received thrashings from Reading (6-0) and Chelsea (5-0 twice), further highlighting Harry Redknapp's claims for a quality youth system to be put in place at Portsmouth Football Club.
Paul Hart, you've got a job on mate!