The 16-year-old, flown from Pakistan to the UK for emergency treatment in October after being shot in the head by a Taliban gunman, told a 1,000-strong crowd outside the library that even "one book, one pen, one child and one teacher can change the world".
"We must speak up for the children of Pakistan, India and Afghanistan who are suffering from terrorism, poverty, child labour and child trafficking," she said. "Let us help them through our voice, action and charity. Lets us help them to read books and go to school."
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