Defence Secretary Michael Fallon has told the House of Commons: 'We will always defend the right of the Falkland Islanders'. He said he had approved the "return of military support helicopters" with two Chinooks operational next year to allow "24/7 tactical mobility".
"We will be renewing the ground-based air defence system when Rapier comes out of service around the end of the decade. We will also maintain our commitment to provide a Falkland Islands patrol vessel," he added.
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Rain will hang over Scotland for most of the day, wind in the north and sunshine in the south.
In a tweet the president called the missiles "small weapons" and said the tests were not a concern for him.
The run is the inaugural event for the Ruth Strauss Foundation, founded by Strauss in memory of his wife who died last year.