The inside of the belt has been mainly lined with a tan leather backing.
Possibly a Yeomanry regiment - but you might know differently?
So far, the majority opinion suggests that the mystery belt is from the Lifeguards, one contributor being sure that he had seen something similar in a military publication.
Others felt that the tan leather lining could have been added by the saddlers of the Household Cavalry, to stop the belt from stretching and from rolling over, at the top, when worn.
Other suggestions have been Royal Fusiliers (City of London Regiment), the Royal Welch Fusiliers and the Leicestershire Yeomanry. It has been stated that the Lifeguards belt is more of a scarlet, than a maroon, which still leaves a slight doubt as to it's definite origins.
The latest suggestion from a contributor confirms that the belt illustrated is Household Cavalry - 'I have unearthed the letter I received with the belt I bought from the PRI at Combermere Barracks, Windsor several years ago. The belt I have is exactly the same colour as the one in the photograph and, in addition, I have now been given another belt by an ex-member of HCMR; the same colour and which has the tan leather lining which he confirmed was made and fitted by his saddler. I also have a belt, again from the PRI, and the supporting letter from 1 Welch Fusiliers, their belt has a much brighter maroon stripe than the HCMR.'