A flotilla will travel along the Thames from Tower Bridge to Westminster Bridge and back as part of the celebrations for the Queen's 90th birthday.
The flotilla will include the row barge Gloriana as well as Havengove, the vessel used for Churchill's funeral.
Between Westminster Bridge and Lambeth Bridge, the procession will turn and be joined by watermen's cutters before returning to the Tower of London in time for for the gun salute at 1pm.
Tower Bridge will lift at 12.55pm.
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