The incident took place at 7.55pm on Monday, 2 May.

An ambulance crew, who had just delivered a patient to University College Hospital, parked in an ambulance bay.

A male crew member, who was outside the vehicle, was approached from behind by a male who pushed a knife against his back.

It was fortunate that the victim was able to diffuse the situation and the suspect eventually backed away, placing the knife in a bag and leaving the scene.

Police are very keen to hear from anyone who knows who the man is.

If you can identify the male in the picture please call 101 or Tweet @MetCC quoting 6309/2MAY.

To remain 100% anonymous call the independent charity Crimestoppers on 0800 555 111 or visit Crimestoppers-uk.org.