She seldom makes public speeches, instead preferring pre-recorded addresses such as the Christmas speech, or scripted ceremonial speeches such as at the opening of Parliament or at State banquets.
The Queen will address the nation from a newly built railway station in Tweedbank, near Galashiels.
It is expected that she will speak as she unveils a plaque to officially open the Borders Railway line, to the sound of a brass band. However, a final decision on the nature of the speech will be made next week.
Queen Elizabeth II acceded to the throne aged 25 following the death of her father King George VI on 6 February, 1952. On 9 September she will have reigned for 63 years and seven months.
The record for longest serving monarch had previously been held by Queen Victoria, having reigned for 23,226 days, 16 hours and 23 minutes.
King Bhumibol Adulyadej of Thailand is actually the world’s longest reigning monarch. The 87-year-old, who rose to the throne in 1946, is a reclusive king who is rarely seen in public.
