Biometric identification systems automatically recognize individuals by physiological characteristics. The first biometric, and the one most widely used, is fingerprint identification. Fingerprints have been accepted in the courtroom as undeniable evidence of subject identification for over a century. Other biometric identification systems being developed for an added layer of security or as a different means of verification and recognition include palm prints, handprints, retinal scans, voice recognition and signature analysis. The next biometric to be widely used will probably be facial recognition. The technique is at the same level of accuracy as fingerprints and can be used against a composite. The United Kingdom already has in operation surveillance technologies using facial recognition to scan a crowd and run facial images against a list of known terrorists.