1. London

Warship's Thames Exercise

The Royal Navy's largest warship has sailed up the Thames to take part in military exercises ahead of the Olympic Games. The eight day 'Olympic Guardian' operation has also seen rapier missiles stationed in Blackheath and fighter jets in the skies.

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Video: HMS Ocean eases through Thames barrier

Royal Navy warship HMS Ocean has arrived in London to take part in security drills ahead of the Olympics.

The ship completes the military presence in London for Operation Olympic Guardian.

Typhoon jets have also been stationed at RAF Northolt, puma helicopters are operating from Ilford, and ground based air defences are being tested with dummy missiles at six sites across London.

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