Around half an hour after the visit from the Queen, William, Kate and their baby were seen being driven away from Kensington Palace.
The Duchess was sitting in the back of the vehicle next to the baby seat while the Duke was a front-seat passenger.
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BA said the strikes will impact "only 1 per cent of our total scheduled flights across the three days."
It's another mild day in the north and west, but cold in the south and central England.
The singer, songwriter and rhythm guitarist for the British rock'n'roll band died on Christmas Eve aged 68.