A manslaughter trial was also told on Tuesday how her parents rushed to the site in Dorset on 10 September 2017, after telephoning Broughton as Michie overdosed and hearing her “screeching”.
However, Broughton insisted she was fine and later referred to Michie as a “drama queen”, jurors heard.
Broughton, of Enfield, north London, denies both manslaughter and supplying Michie the drug.
Prosecutor William Mousley QC said Broughton failed to get help because he feared the consequences of a suspended jail term he was handed one month earlier, Winchester Crown Court heard.
He added that the drug “had a terrible effect upon [Michie], leading to her death after a significant period of suffering in woods close to the festival site, all of which he must have observed”.
Jurors were told Broughton filmed Michie, a dancer and yoga teacher, as her condition deteriorated.
In clips played to the court, she can be heard repeatedly shouting at Broughton to telephone her mother, Carol Fletcher-Michie, but he tells her to “put your phone away”.
Ms Fletcher-Michie eventually spoke to Michie at 6.48pm and grew concerned as she “could hear her screeching”.
Mr Mousley said: “She told her husband that they needed to get to her and they dropped everything to travel from north London to Dorset.”
Her brother, Sam, also contacted Broughton and urged him to seek medical help.
But Broughton sent his girlfriend’s sibling a message which said “call back in an hour” and referred to Michie as a “drama queen”, the jury heard.
Jurors were told Sam Michie also knew Broughton and had been given drugs by him previously.
Mr Mousley added: “In addition, during that extended period of time when they were together he filmed her on a number of occasions.
“He filmed her when she was disturbed, agitated, and then seriously ill over a period of hours.
“He even did so, the prosecution suggest, after she was apparently dead.”
He said that a month before the incident, Broughton was handed a 24-week prison sentence suspended for one year.
Broughton has also previously pleaded guilty to supplying 2-CP to Michie and her friend at Glastonbury Festival in June 2017 – a different incident to the suspended sentence – the jury heard.
Mr Mousley added: “His failure to get her treatment which may well have saved her life was borne of selfishness and in self-preservation.
“Because to have done otherwise, to have acted positively, he knew would have exposed him to the possibility of arrest and prosecution for a criminal offence punishable with imprisonment.”
Mr Mousley said that a medical expert, Professor Charles Deakin, “didn’t believe that Louella’s death was inevitable if she had received medical help”.
Prof Deakin found there was a “90 per cent” chance of survival with early intervention, jurors heard.
Defending Broughton, Stephen Kamlish QC said he and Michie “were in love with each other”.
He said: “You will hear from experts that no-one has ever been known to die from taking this drug or taking an overdose.”
He said Michie had acquired the 2-CP herself, adding: “This is not gross negligence manslaughter.”
The trial continues.
Additional reporting by PA
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