Flat Bastion was originally called Bastion Santiago or Saint Jargo. The Bastion could be accessed by a gate that has now been blocked up, running under Charles V Wall from Hargreaves Steps. The area originally had a small magazine for the two batteries. By the 1880s the batteries had been removed and the area used for recreation and accommodation by the Royal Engineers.
This whole area has now been cleared, apparently for redevelopment.
The Bastion originally mounted:
- 2 x 12lbs Carronades
- 4 x 12lbs guns.
By 1859 this had been upgraded to:
- 4 x 32lbs
- 4 x 8ins Howitzer.
By 1886 all the guns had been removed.
The East side, or the top of the Bastion, contained Flat Bastion Magazine.
Immediately adjacent to the Bastion is Hargrave’s Barracks and Hargrave’s Parade, predominantly used by the Royal Engineers. Prince Edward’s Gate lies between Flat Bastion and Hargrave’s Barracks and was named after the fourth son of George III, the father of Queen Victoria.