The police, some in full-on counter-terrorism uniform, others in plain clothes have been trained to spot the tell-tale signs that a person may be carrying out a reconnaissance mission — or engaging in other criminal activity.
Supported by dogs, the territorial and marine unit, the officers will patrol busy areas of Wandsworth and Lambeth.
'Psychology of Criminals'
According to London's Metropolitan police service, its new operation is based on "extensive research into the psychology of criminals and what undermines their activities."
The tactic is known as Project Servator has been developed over the past five years by experts at the Center for Protection of National Infrastructure (CPNI) and is already used by the London's City Police and British Transport Police in their attempts to disrupt terrorist activity.
The project has been launched at Vauxhall Bridge in London, not far from Westminster and headquarters of MI6 and officers are also appealing to members of the public to report anything suspicious.
"We cannot do this alone and I urge Lambeth's communities to report any unusual or suspicious activity they see. If you see police officer where you are, please speak with them about how you can help keep your community safe," Chief Superintendent Richard Wood, borough commander for Wandsworth said.
Scotland Yard says the launch of the so-called Project Servator isn't "in response to a specific threat," meanwhile the UK's official terrorist threat level remains at "severe" which means an attack is highly likely.