An individual from Poland who asserted to be Madeleine McCann "pursued that myth" and stalked the child's family by sending emails, placing telephone calls and turning up at their residence, a trial was told.
The first defendant and Julia Wandelt conducted a "systematic intimidation", the court was informed, and in Ms Wandelt's case, that lasted for thirty months.
At the trial's commencement, jurors were told Ms Wandelt consistently asserted she was the missing child and was taken and taken to the European nation.
Ms Spragg and Ms Wandelt each deny a charge of harassment resulting in serious alarm and distress to Kate and Gerry McCann between mid-2022 and early this year.
The child's vanishing in 2007 - at the age of three during a vacation in Portugal - is one of the most widely reported missing child cases and remains unsolved.
The prosecutor also spoke of the global attention that Madeleine's case had directed toward the parents.
"One of many devastating outcomes for the McCann family has been their constant inability to avoid the spotlight of publicity that accompanied that incident.
"The attention they have received has not always been sympathetic, at times quite the opposite.
"There continues to exist a group of individuals who continue to fail to acknowledge their situation and spread conspiracy theories.
"Unfortunately, these accused individuals belong to that second category."
Escalating Behavior
Testimony revealed from June 2022, the defendant had started telling to "any willing listener" that she was the missing child.
Legal authorities said that, in early 2023, Ms Wandelt was in communication with a Polish charity created to help with historic missing persons cases and offer support and advice to people seeking those who had gone missing.
Based on court testimony, Ms Wandelt first claimed she was missing German girl from Germany.
But after these assertions were ruled out by the organization, the accused then reached out to the charity with a belief she could be Acacia Bishop - a missing baby from Utah in the United States - before messaging them about her insistence she was the British missing child.
'Failed to Stop'
Her belief escalated to an effort to contact the medical facility where both the McCanns worked.
A 20-minute call to the switchboard resulted in a notification from the NHS trust's communications manager to the investigation team, the British investigation into the disappearance.
Court proceedings revealed the defendant made further attempts to contact the authorities and then Mr McCann directly via email in June 2023.
In one email, she wrote: "I could be your daughter, there's a chance I am the missing girl."
She added people were "trying to cover up the story" and asserted there were similarities between her and Madeleine, including having scars in the identical locations.
But her efforts went without response, which the prosecutor said "failed to discourage" Ms Wendelt - who then made contact with Madeleine's younger sister Amelie via social media.
Telling her she was her "sole chance", she transmitted doctored images to show they were "somehow related" and asserted possessing recollections of events prior to disappearance, the trial was told.
These assertions, the proceedings revealed, were repeated in this year when Ms Wendalt is alleged to have "repeatedly" messaged Mrs McCann's cell phone over the span of 24 hours - referring to her as "mother", asserting memory of feeding the family's son the boy, of playing children's games in the back garden of the residence in the Leicestershire village, the English county, and of the night the disappearance occurred.
In a communication, she said: "I recall you visited my room before the incident, rubbed my head and said 'I love you and I will find you'."
The trial of the first defendant, of Jana Kochanowskiego in the Polish city, Poland, and the second defendant, of Caerau Court Road in the Welsh city, proceeds.
