The judge in the trial of Tulisa Contostavlos told the jury there were "strong grounds" to believe an undercover reporter had "lied" at a hearing before the trial began.
Judge Alistair McCreath was speaking as he threw out the case at Southwark Crown Court.
The Sun's Mazher Mahmood - known as the 'Fake Sheikh' - had posed as a wealthy film producer when he met Contostavlos at a number of hotels and restaurants.
The former N-Dubz singer strongly denied that she had helped broker a drug deal between Mahmood and her rapper friend Michael Coombs, also known as Mike GLC.
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Dominic Chappell, the man who bought BHS for £1 from Sir Philip Green, is to be prosecuted by The Pensions Regulator.
The 5,000 ecstasy pills had an estimated street value of £36,000.
Police say it is "too early" to know if the body is that of journalist Kim Wall, who is believed to have died on board an amateur submarine.