The Queen will visit the Corps of Royal Engineers today to celebrate their 300th anniversary.
She will attend Brompton Barracks in Chatham, Kent, where she will inspect 140 troops and view examples of heavy specialist equipment used by soldiers.
After a parade, the Queen will meet military personnel from the Corps of Royal Engineers, of which she is colonel-in-chief.
The monarch last visited the corps at Brompton Barracks in 2007.