Nelson Mandela's spokesman Mac Maharaj said he was being treated in hospital for pneumonia.
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The news that Jeremy Clarkson, Richard Hammond and James May are to present a new show on Amazon Prime has been met with a mixed response.
Authorities say Ai Weiwei failed to disclose a previous "criminal conviction" - though his supporters say he was never even charged.
The supermarket made the change after getting feedback from customers who said they felt under pressure as they finished their shop.