Prince William approached journalists from the Guardian and said: “Why don’t you put your notebook down and give us a hand with the sandbags?”
William and Harry were spotted along with Prince Harry helping move sandbags in flood-hit Datchet.
However after reporters agreed to help, aides intervened and said it would not be possible due to a lack of appropriate clothing.
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The Duke of Cambridge said the new prince was "behaving himself" and sleep was "going reasonably well so far".
The challenge came as Theresa May vowed no stone would be left unturned in putting right the status of the Windrush generation.