Thousands of photographs and CCTV images of unidentified suspects have been uploaded online in an effort to assist officers searching for wanted individuals.
Users simply enter their postcode into the application, known as Facewatch id, to access the images relevant to their neighbourhood.
If they can then identify any of those sought they can contact police through the technology to provide confidential details about the suspect.
Metropolitan Police Assistant Commissioner Mark Rowley, responsible for Specialist Crime and Operations in London, said he expected the app to lead to increased arrests.
"The general public can support us in this - both by providing us with images - and then helping us to identify those who are responsible for committing crime," he said.
"I would encourage as many people as possible to use the app to view these images and send in information."
The application is available to users of all those using BlackBerry, Apple (Iphone and Ipad) or Android technology.
The service currently only covers London but will be rolled out to across the whole of the country over the coming months.
Some 2,000 images of people the MPS would like to identify are already on the system and photographs from City of London Police and British Transport police for London are to be added soon.
Simon Gordon, chairman of Facewatch Ltd, the developers of application, said the software was available free to any police force in the UK.
He added: "By using the very latest technology we have created a simple, easy to use and highly relevant way for the public to assist in the huge job of managing the capitals CCTV image database."
Detective Chief Inspector Mick Neville, head of the Visual Image Identification and Inspection Office of the MPS, said: "The Facewatch id application will help the police to catch more criminals and by showing that CCTV is working it will help to stop crime as well."