Actually trying under Portuguese law didn't work out that well because of the total disruption of the civil administration in the country so offenders were usually tried under British military law before a General Court Martial. However, the snag was that under the laws of procedure for GCMs, evidence had to be given in person, written depositions were not accepted. If the the GCM took place at a distance from the scene of the crime, it was often difficult to get witnesses to testify and, in addition, many Portuguese were reluctant to testify.

Wellington and his provosts, however, had the power of summary punishment, often referred to as a "drum head court martial" which could punish an offender on the spot, particularly if his crime was a grievous one and a swift deterrent was required. W used summary punishment sparingly, but he did use it, 3 soldiers who were stupid enough to break into a house in the village where his headquarters was situated were executed by summary punishment.

This letter was written early in the Peninsula campaign, matters began to improve in the next two years and by 1812, GCMs were in almost permanent session and offenders against the civil population of Portugal and Spain were being tried fairly quickly, barring problems with witnesses. In 1813, the Detachment General Court Martial was introduced by law, which was more or less a sanctioned version of the drum head court martial (as the DHCM or summary punishment did not have a legal foundation after about 1700 although it was used throughout the 18th century). A DGCM could be convened quickly, on the spot, required fewer officers on the board and, like the GCM, could pass sentences of capital punishment.

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