The Prime Minister has pledged 1,000 British troops to a "high readiness" Nato force, Downing Street has said.
When the force is ready, in late 2015, it will be capable of deploying within 2-6 days.
British troops will make up a substantial portion of the multinational force, which will total 4,000 troops.
Angus Raffle, 8, says his surprise meeting with the President at Stonehenge was "awesome". His mother says she "squealed like a teenager".
The language has been ramped up at this Nato summit, yet caution appears the order of the day after the mistakes of recent history.
The US President's motorcade pulled up at the school with his black stretch limousine bearing a Welsh flag for the first time in history.