A spokesman for Mohamed al Fayed, whose son died alongside Princess Diana in 1997, said he had no comment to make.
But it added that he will be "interested in seeing the outcome", and that he trusts the Metropolitan Police will investigate the information "with vigour".
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An ejector seat manufacturer is to be prosecuted over the death of Red Arrows pilot Sean Cunningham at RAF Scampton in November 2011.
Police said the "active shooter" had since been shot by officers and they were not seeking any other suspects.
Rain will continue spreading in from the southwest, remaining heavy, especially in western areas.