Fellow officers stand in unison during the romantic proposal, which ended with a yes and an enormous cheer from the crowd. In the video, which was shot outside Hamleys in Regent Street, the policeman holds the hands of his shocked partner and pops the question.
Thousands of people erupted upon the loved-up boyfriend's acceptance as the officer joined the rest of the force and marched away in the parade.
Publishing an image of the adorable moment with the caption 'He said yes!' on Twitter, MetLGBTNetwork later shared another image - however this time of a different couple.
The second loved-up duo appear to both be in the police force, and were photographed as one of the officers offers the other a ring.
Photo of the second couple who are both police officers below...