In a move which could put his party at odds with its Conservative coalition partners, the Chief Secretary to the Treasury admitted Britain faces a "big decision in 2016" over alternatives to the current weapon system.
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It’s the second country on Harry and Meghan's four-nation tour - the first thing you learn here is they give visitors a warm welcome.
However, skies will be cloudier in northern and western Scotland with rain and drizzle.
The Duchess was presented with a bouquet of flowers on arrival.