Greater Manchester Police has been asked by the Metropolitan Police to review its "Plebgate" investigation.
The Met said the move is standard practice in a high profile investigation.
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Last minute preparations are going on at the Church of St Mary Magdalene where Princess Charlotte will be christened.
Princess Charlotte is being christened on Sunday at Sandringham in Norfolk in only her second public appearance since she was born.
Thunderstorms clear the North, leaving a dry and warm day with sunny spells.