Thesurface-to-air weapons were placed on buildings across London last month as part of the Olympic Guardian security exercise, which also saw fighter jets positioned at RAF Northolt for the first time since World War II. 

Despite fears over some missiles being deployed on residentialbuildings overlooking the Olympic Park, defence secretary Philip Hammondinsisted that the operation ‘achieved its objectives’. 

Mr Hammond said the weapons, which would be used to protect against9/11-style attacks, would not pose a risk to people on the ground. 

He told the Commons: ‘We will now consider military advice andmake a final decision about the deployment of ground-based air defencesystems.’ 

Residents living close to possible missile sites in east London –including Bow Quarter and Blackheath – would be ‘made aware of allramifications’, he added. 

Last month, one resident described the plan as ‘totallyunsuitable’. Mr Hammond did not reveal when a final decision would be taken. 

While the capital prepares for a major security operation, driversare being warned to avoid 175km (109 miles) of central London roads frommid-July. 

Motorists should steer clear of the Olympic Route Network, whichincludes 48km (30 miles) of reserved Games lanes, transport bosses said. 

It is set to open from July 25, two days ahead of the Games’opening ceremony, and will be a key route for athletes, officials andsponsors. 

New road markings will go down from July 1, while changes to morethan 1,300 sets of traffic signals are scheduled for the same day. 

Transport for London claimed the adjustments would have minimalimpact, as they will be balanced out by a ban on planned roadworks along theORN and A and B roads.