Lord Deighton says to London Assembly member John Biggs that many tickets were sold below market value - 340,000 tickets were given to school children and troops.
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A 24-year-old man has been arrested on suspicion of murder after the body washed up on the Thames shoreline.
Seven people have now been arrested after a man died from serious head injuries
The 38-year-old officer was on his way home from a night shift when he collapsed. His death is not being treated as suspicious.