Syed, from Hounslow in west London, will be sentenced at a later date. He pleaded guilty to a plot running from April to September 2016 to get materials for a bomb to stage attacks.
The judge warned him this was “a grave offence, and he would consider if a life sentence was merited”.
Syed’s brother, Nadir Syed, 24, was last year convicted and jailed for life for plotting to behead a poppy-seller or police community support officer on Remembrance Sunday.
The Elton John concert researched by the teenager fell on the anniversary of the 9/11 attacks on the United States.
He was arrested in September 2016 and when detained by officers said “alright”. He told an undercover officer of his desire to get bomb-making material and was inspired by Islamic State.
/Guardian/
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