Electoral politics is a bloodsport and some of the toughest fighters in the game are the campaign strategists who hone and sell their candidate's message.

Lynton Crosby ran winning campaigns in his native Australia for former prime minister John Howard. In the UK he twice helped Boris Johnson win the London Mayor's office.

He tells Stephen Sackur that he doesn't try to change voters' opinions but gives them the information to make an informed choice.

You can watch the full interview on BBC World News on Monday 2nd July at 03:30, 08:30, 15:30 and 20:30 GMT and on the BBC News Channel on Monday 2nd July at 04:30 BST and on Tuesday 3rd July at 04:30 BST.

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