The Prime Minister said that Scotland gains from Britain's membership to international networks such as the Commonwealth, NATO and the EU.
He said it send a wider message that Britain "counts for something in the world".
More top news
Odense zoo plans to publicly dissect a year-old lion - undeterred by outrage at giraffe who was killed in Copenhagen last year.
The Duke and Duchess of Cambridge met young people who have battled mental health issues on Saturday.
Former Chancellor Lord Geoffrey Howe was Margaret Thatcher's longest-serving Cabinet minister, also taking on the role of Foreign Secretary.