Canadian Prime Minister Markey Carney has said that "high level" talks are taking place with the US about joining its proposed "Golden Dome" missile defence system, aimed at countering futuristic threats. US President Donald Trump unveiled the plan for the new missile defence system on Tuesday, announcing an initial total cost of $25bn (£18.7bn). He said Canada was interested in joining the project. There are doubts from experts on how the US would deliver a comprehensive system and it is unclear how Canada would participate or how much it would pay. "It's something that we are looking at and something...