The alleged incident took place outside a London bar near Buckingham Palace and left two royal footmen requiring hospital treatment, the Daily Mail reported.
A Ministry of Defence (MoD) spokeswoman confirmed three guardsmen were being investigated by the Metropolitan Police following an incident on Friday July 24.
The Coldstream Guards, recognised by their red jackets and black bearskin hats, have a ceremonial role as protectors of Windsor Castle and Buckingham Palace.
The altercation was said to have happened outside the Greenwood Sports Pub on Victoria Street – about 800m from the palace – as a group of royal footmen were attending leaving drinks.
A source told the Daily Mail that a “bit of banter” developed between the footmen and a group of about four soldiers outside the bar around 11.45pm.
However, it escalated when a guardsman “grabbed hold” of one of the female footmen, resulting in a male footman stepping in to stop him.
“All of a sudden it was a full-scale punch-up. And the soldiers were more used to fighting than the footmen are. They got quite badly injured,” the source claimed.
One 20-year-old man suffered a fractured eye-socket, while another had a fractured jaw and required stitches in his tongue, the source told the paper.
Two other footmen were said to have been less seriously injured.
An MoD spokeswoman said: “We can confirm that three guards are being investigated by the Met police following the incident in London on July 24.”
The Coldstream Guards are the oldest continuously serving regiment in the British Army and is based at Victoria Barracks in Windsor, west of London.
It is primarily an infantry unit, but is well known for its high profile ceremonial duties.
The Met has been contacted for comment.
