British Forces at Cadiz 1810-1814: Organisation, Strength, and Losses
Between 1810 and 1814, the British Army maintained a military presence at the Spanish city of Cadiz. Not only was this a matter of political importance, due to the British need to ensure that the city did not fall to France, but it also held strategic advantages. Along with the similarly sized forces maintained at Gibraltar, troops from the Cadiz garrison could be used in offensive operations along the adjacent coast – this was most obviously the case during the Barossa campaign of 1811, when Graham’s British contingent under La Pena utilised manpower from both garrisons. Additionally, troops could be rotated through Cadiz to the main field army under Wellington, thus allowing them to become accustomed to the Iberian climate before commencing active service. In like fashion, units that had fallen into poor condition due to the rigours of duty with the field army could be sent to Cadiz to recover themselves, whilst still being available for rapid recall if required.
Yet, despite this importance, the composition of this force, and its internal organisation, has not previously been detailed. By using information from the journal of operations kept under the successive British commanders, supplemented by additional details taken from their correspondence with Horse Guards, the changing organisation of the force can be tracked in order to provide a complement to C.T. Atkinson’s detailing of the main army under Wellington. In addition to this, Monthly Returns kept in The National Archives enable the strength of the units concerned, and their losses, to be tracked.  Throughout this article, unit strengths where given are for rank and file only, and are given in the form (effective strength/total strength).
From the outset of the Peninsular War, it had been considered an important objective for Britain to ensure that Cadiz, being a vital and strategically important naval port, did not fall into French hands, and this resulted in some extremely underhand and provocative attempts to force the Spaniards to permit a British garrison to enter the place. Such measures had been successfully employed to induce the Portuguese to permit a landing on Madeira, but, with regards to Cadiz, a natural and inevitable suspicion of the old enemy, who had, after all, until recently been engaged in enforcing a blockade of the same city, meant that no forces were allowed to land. British preparations had progressed to the extent of embarking a brigade from Lisbon in February 1809, composed of:
Commanding the Force: Major General John Randoll Mackenzie
The Spanish refused to allow Mackenzie to disembark, and his troops returned to Lisbon on March 11th.
Until the autumn of 1809, Cadiz continued to be garrisoned solely by the Spanish, whilst British efforts were focused on the campaigns of Oporto and Talavera. The situation altered drastically, however, with the collapse of the Spanish armies in southern Spain following Wellington’s withdrawal post-Talavera and the Spaniards’ doomed attempts to continue the failed offensive single-handed. Spanish defeat at Ocana on November 18th-19th 1809 allowed for the subsequent French drive through Andalusia, and left only a slender and disorganised force to hold Cadiz. The “Return of the Allied Forces in the Island of Leon, February 24th 1810”, shortly after the arrival of the first British, details the Spanish forces under Captain General the Duke of Albuquerque as follows:
It was also noted that “there are between two and three thousand volunteer infantry doing duty in Cadiz”. In contrast, the French had, as of January 10th 1810, 55,723 effective rank and file in the three Corps d’Armée operating in Andalucia, of which the 21,882 men of Marshal Victor’s I Corps were directly operating against Cadiz. This disparity in numbers forced the Spanish to accept the need for assistance.
In the favour of the Spanish defenders, and the allies who would soon join them, was the fact that Cadiz was a natural fortress, extremely difficult to attack from the land. Although this article is not intended to be a narrative of the events of the siege, an understanding of the geography of the city and its environs is necessary both to appreciate why such a sizable garrison was required and to understand the location of the various points where troops were posted.
As can be seen from the map above, the city of Cadiz was situated at the tip of a long sand spit running out from the Isla de Leon, which was itself separated from the mainland by salt marshes. French siege operations were concentrated around the two areas marked on the map as French Camps, with that to the north being initially concerned with reducing Fort Matagorda, which remained in allied hands at the outset of the siege. Because of the strength of the Cadiz/Isla de Leon position, no active attempts at assault were made, and the situation took on the character of a blockade. However, allied naval superiority meant that the French could never hope to cut the city off completely from supplies and reinforcements. Seapower also facilitated counterattacks against the besiegers: maintenance of a military presence would therefore not only permit the British to shore up their ally but also to hit back at the French.
 “Journal of the proceedings of the British Army serving at Cadiz and the I. of Leon” [hereafter cited as Cadiz Journal], in TNA, WO28/339-341.
 TNA, WO1/247, 252, 264-266.
 Included as Appendix II to Sir Charles Oman, Wellington’s Army 1809-1814 (London: Edward Arnold, 1913), pp.343-373.
 TNA, WO17/1486-1488.
 List of units from Ron McGuigan, “The Origins of Wellington’s Peninsular Army, June 1808-April 1809”, in Rory Muir et al, Inside Wellington’s Peninsular Army 1808-1814 (Barnsley: Pen and Sword, 2006), p.64; strengths from return of British forces in Portugal, March 1st 1809, in TNA, WO17/2464. The KGL artillery with Mackenzie is inexplicably returned as comprising only four rank and file; the 2/9th included men from the 1/9th left in Portugal when the main body of the senior battalion went into Spain with Moore. It may be assumed that the bulk of the non-effective rank and file remained in Lisbon.
 Summarised from Sir Charles Oman, A History of the Peninsular War (Seven Vols. London: Greenhill, 2004), Vol.III, pp.67-152.
 TNA, WO1/247, pp.25-26. All strengths are total rank and file.
 Computed from Oman, Peninsular War, Vol.III, pp.532-539.
Placed on the Napoleon Series: August - September 2009
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