Book review - Wellington and the Lines of Torres Vedras

The Defence of Portugal during the Peninsular War, 1807 – 1814

By Mark S. Thompson

Helion, Warwick, 2021, 224pp, Images: 28 colour and 50 b/w illustrations, maps and diagrams

9781914059858 - Paperback

Reviewed by BRIG Chris Roberts (Retd.)

In this meticulously researched book, Mark Thompson delivers a comprehensive study filled with a wealth of information on the planning, construction, and defence of the Lines of Torres Vedras. Along the way, the author challenges some earlier held views, providing firm evidence to support his position. Accompanied by a raft of maps, charts, diagrams, illustrations, and photographs, Thompson’s book should satisfy anyone wishing to know about this engineering feat that defeated the third French invasion of Portugal in 1810-11.

The book starts by setting the background to the defence of Portugal, beginning with the French occupation of 1807-08, and analysing the claims as to who initiated the concept for the Lines.  Thompson then details the planning, nature and construction of the fortification. In doing so, he relies heavily on the diaries of various officers, including the correspondence between Lieutenant Colonel Fletcher, Royal Engineers, who was entrusted with building the Lines, and Wellington, the Commander-in-Chief. Presented chronologically, and despite the excellent maps and diagrams, the reader may have difficulty following the course of the construction of the numerous forts and redoubts. With the unfamiliar location names, and the extent of the ground over which the Lines were built, it may have been useful to have included a large fold-out or separate map to enable the reader to follow the text without having to continually turn pages to consult the relevant map embedded in the text.

While the idea of the concept of defence in depth is often associated with the German Army on the Western Front during the Great War, the approach was also employed in the Lines of Torres Vedras; with two extensive lines of entrenchments and fortifications north of Lisbon, a third covering a possible evacuation site west of the city, and a fourth on the south bank of the River Tagas. Given the difficulties with weather, the available manpower, and the sheer extent of the defences, Thompson’s narrative highlights what a remarkable feat their construction was. Nor is the Royal Navy’s contribution neglected, both in the fortifications and along the River Tagas on the right flank of the Lines. Contributing to the narrative is an interesting chapter on the various systems of communication employed within the Lines, back to Lisbon, and along the river. Informed by several diagrams and maps, the reader gains a clear understanding of how each system worked, the location of the signal stations, and the speed with which messages could travel over long distances.

After outlining the third French invasion of Portugal and the Allied retreat, Thompson then focuses on Wellington’s disposition of forces within the Lines and the French operations in front of them, together with the Royal Navy’s activities and those of the Allies on the left bank of the Tagas River before the French were forced to retreat back into Spain. Although well written, on occasion it is difficult to follow the flow of the activities. Nonetheless, Thompson delivers what is probably the most comprehensive account of this period (October 1810 to March 1811), including detailing the continuing work on strengthening the Lines.

Supplementing the numerous black and white maps and diagrams embedded in the text, is a sixteen page colour section providing illustrations, diagrams of construction, photographs of current sections of the Lines, and a two page map showing all of the forts and redoubts in the first two lines north of Lisbon.

That the Portuguese authorities are preserving and protecting the Lines, and developing their tourist potential, makes Thompson’s study especially valuable. While this book may not appeal to the lay reader, it certainly will for those with an interest in military engineering or the Peninsular War, and is a must have for students of the war and those intending to visit the Lines.