Nicholas Jacobs has been remanded in custody until Friday by Westminster Magistrates' Court after being charged with the murder of PC Keith Blakelock.
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Dashcam footage captured the tree crashing down onto 40-year-old Sarah Robb's BMW just after she left her home in Syston on Thursday.
The teenagers, aged 19 to 15, appeared in custody at Westminster Magistrates' Court on Saturday, supported by their families.
Labour must "broaden its reach" in order to win votes off the Conservatives, deputy leader Tom Watson has said.