Royal Marines and Scotland Yard took command of the River Thames yesterday in a determined show of strength as part of a security exercise for the London Olympics called Operation Woolwich Arsenal Pier.

Elite military and police teams joined forces in a combined exercise to give a glimpse of the sheer scale of the Britain’s biggest peacetime security operation yesterday.

The British forces show was designed to test the water for the joint operation, and to illustrate the country’s readiness against terrorism.

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 Royal Navy Lynx helicopter for the 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.

Royal Marines and Scotland Yard took command of the River Thames yesterday in a determined show of strength as part of a security exercise for the London Olympics called Operation Woolwich Arsenal Pier

Speaking on the shores of the Thames, Chris Allison 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.”

Despite a heavy military presence on show today, Chris Allison insisted the sporting event would remain a “blue games”.

The Thames runs directly past the O2 Arena, which will be known as the North Greenwich Arena for the purpose of the Games, when it will host events including gymnastics.

The river will also be used to transport tourists between venues via water buses and a new cable car.

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,” Chris Allison said.

“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.”

[youtube 5DSbPSbezHc]