Xolile Mngeni, 25, who was convicted of firing the shot that killed Anni Dewani on her honeymoon, has been handed a life sentence by a judge in South Africa.
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It is "clear" ministers cannot proceed with the current Bill, Sir Keir said, threatening to "work with all sides" to ensure revisions.
Rain will clear eastwards through Sunday but it will remain blustery.
Donald Trump has indicated he does not intend to block the release of thousands of secret files about the assassination of John F Kennedy.