80 young people from 40 London schools, who had gathered to celebrate their end of term achievements, could hardly believe their eyes when Will Smith walked onto the stage.
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One of the teenagers was left so badly burnt doctors say he may lose his eyesight.
Jame Murray's challenge is to deliver Mr Khan's manifesto pledge to build more than 50,000 new homes a year - half of them affordable.
Ryan Lee was removed from the finishers' list because he was not picked up by the 5k checkpoint.