Forces gear up to protect Olympics
Elite police and military teams have joined forces to give a first glimpse of Britain's biggest peacetime security operation.
Scotland Yard and the Royal Marines took to the River Thames in a show of strength against terrorists targeting the Olympics.
Around 100 marines and 50 officers rehearsed a string of high-speed drills amid fears attackers could use the waterways to launch onslaughts on London landmarks.
About 50 marine police officers in rigid inflatables and fast response boats were joined by up to 100 military personnel and a Lynx Navy helicopter for the familiarisation exercises.
Assistant Commissioner Chris Allison, head of the force's security operation for the Games, said a Mumbai-style terror attack was one of a host of potential threats to the Games.
Speaking on the shores of the Thames, he said: "There is no specific threat from the river but we would be failing in our duty to ignore it at Games time. What you have seen today is the sort of things we can do."
Typhoon jets and HMS Ocean, the largest ship in the Royal Navy's fleet, will eventually be deployed to protect the London 2012 Games along with up to 13,500 military personnel. "If we need the military support, it is there," Mr Allison added.
"All of our planning is designed to mitigate against potential risks during the summer of 2012, and this is an example of where we will be using specialist military capability to support us.
"This exercise is not in response to any specific threat, but is part of our planning to pre-deploy certain specialist assets to bolster our operation.
"This will be a summer like no other in London. The Thames runs through the very heart of our capital and will be a popular place for people who want to be part of the Olympic spirit. This is all part of our planning to ensure this summer's events take place safely and securely."