David Flintham - Military Historian

Click here to edit subtitle

The ECW defences of London

At the outbreak of the English Civil War in 1642, London was the country’s chief port and financial centre, the seat of government and, in the Tower of London, the nation’s chief arsenal. With London so strategically important, by fleeing the capital at the beginning of 1642, King Charles I placed his cause at a distinct disadvantage. To many Parliamentarians, it was obvious that the King would attempt to regain the capital, by force if necessary. So, between the autumn of 1642 and the spring of 1643, an 18-km circuit of forts and bulwarks connected by ramparts and ditches was thrown up around London. It was the largest feat of military engineering undertaken anywhere in the country during the conflict and at the time was amongst the largest urban defence systems in Europe.

George Vertue's 1738 plan of London’s defences (above) is probably the most well-known image of what were the largest and perhaps the most sophisticated of any urban defence schemes constructed during the English Civil Wars. Whilst hardly comparing with schemes elsewhere in Europe, in Britain, only those at Oxford come close. However, whilst there are some similarities between the defences of London and Oxford, there are also differences – whilst Oxford’s defences were basically a bastioned circuit, London’s defences comprised, in the main, of a series of forts joined by ramparts and ditches. Whilst there are other examples of the ‘connected forts’ type defence schemes (Bristol and Plymouth for example), it is the size of London’s defences which demonstrate their uniqueness.


Whilst time has erased virtually every trace of London’s defences, in several places their legacy lived on – in the story of one of London’s most famous hospitals, in the development of a part of London now home to one of the world’s most famous museums, the history of one of London’s parks, and finally in the story of the Country’s leading military museums. These sites, therefore, feature large when it comes to looking at the location of the defences, particularly in relationship to modern London. Whilst the stories of such places, together with the scant remains and memorials, are a seemingly inadequate legacy for what was one of the largest constructions in London until the 19th century, yet this, and the accounts written in the 350 or so years since the Civil Wars, commemorate one occasion when Londoners came together in a common cause – the defence of London.


Above is Vertue's map superimposed on a map of modern London (with thanks to Charles Blackwood of the Fortress Study Group for his assistance with this).  Hyde Park fort is one of the two forts highlighted (the other is close to the site of the Imperial War Museum).  In 1644, the Prague-born engraver Wenceslaus Hollar draw this fort.  His sketch can be viewed at the John Rylands Library (click here to view a  digitised version - Hyde Park fort is the subject of the two drawings on the right-hand side of page 31).


Over the years, much of my research into London's Civil War defences has been published. The published works are:


  • ‘The Topography of the Lines of the Communication - Mapping the Civil War Defences of London’ in London Topographical Society Newsletter, 45, (London Topographical Society, 1997)
  • ‘Archaeological investigations into the English Civil War Defences of London’ in London Archaeologist, 8, (London Archaeologist, 1998)
  • ‘Whitechapel Mount and the London Hospital’ (http://www.mernick.org.uk/thhol/whimount.html - Tower Hamlets History Online, 1999)
  • ‘Whitechapel Mount’, Fort, 35, (Fortress Study Group, 2007)
  • ‘London's Fort Royal’, Casemate, 80, (Fortress Study Group, 2007)
  • London in the Civil War, (Partizan Press, 2008)
  • ‘Civil War fortifications of London’ (http://www.fortified-places.com/london/ Fortified Places, 2008)
  • ‘London's Civil War Defences’, Arquebusier, 32, (Pike and Shot Society, 2010)
  • ‘A Tale of Two Forts - London's Hyde Park and St. George's Fields Forts’, Fort, 38, (Fortress Study Group, 2011)
  • ‘The Defence of London’, Military History Monthly, 24, (2012)
  • ‘Fortress Islington’, Journal of the Islington Archaeology & Historical Society, 2, (Islington Archaeology & Historical Society, 2012)
  • The English Civil War Defences of London, (The Stuart Press, 2014)


The hunt for Mount Mill Fort


Simply hundreds of miles of earthwork fortifications were thrown up during the Civil Wars around towns, cities and other places of strategic importance. With a few notable exceptions, these have almost completely vanished, although in a number of urban locations it is still possible to trace their course.


Since the foundations of ramparts make a decent starting point for road-building, many roads follow the course of earlier fortifications. Perhaps nowhere is this more apparent than in Edinburgh where Leith Walk follows the line of the earthworks thrown up in 1650 to resist the invading English army.


In London, several roads follow the Lines of Communication, and in the area known as St Luke’s, their likely course was along what is now Lever Street. However, the course could equally be followed by Dingley Road, slightly further to the north. But both point to the site of Mount Mill Fort as being in an area close to King Square Gardens.


The 1643 specification for Mount Mill Fort called for a battery and a breastwork although by the time of William Lithgow’s journey it had expanded to a lower and outer fort of five angles containing a central and circular redoubt.


During April 1643, Lithgow, a Scottish merchant and traveller walked the entire 18 km circuit of defences. His description includes Mount Mill Fort:


“Thence I marched through Fineberry fields along the trench (enclosing these moorefields), and came to Mount Mil-hill Fort (for all the forts about are [……] and [……] in sight of other), where being arrived, I found it standing on the highway near to the Red Bull. This is a large and singular fortification, having a fort above, and within a fort, the lowest consisting of five angles, two whereof towards the fields are each of them thrice ported, having as many great cannon, with a flanking piece from a hid corner; the upper fort standing circular, is furnished with eleven pieces of cannon reall [Royal], which command all the rest; and upon the bosome top of all standeth a windmill; the lower bulwarks are first pallosaded round about and near their tops, and then in the middle flank between the two ditches strongly barricaded; besides tow counterscarps and three redoubts of lesser importance, yet all defensive. This is one of the chief forts about the city and first erected.”


Lithgow described the defences as "erected of turffe, sand, watles, and earthen work" (and masonry was used in the construction of the gateways ). In his account, he says the “trench dyke was three yards thick and on the trench side twice as high” . The defensive ditch in front of the rampart was about 5.5m wide and 1.4m deep .


There is a contemporary illustration (above) of Mount Mill Fort which appeared in a broadside published 18th August, 1643, titled Malignauts Treacherous and Bloody Plot). The illustration suggests that the windmill (from which Mount Mill takes its name) was contained within the fortifications.


Decommissioned in 1647, an area close to the fort was used as a plague burial ground in 1665, sited, according to Daniel Defoe, on “A piece of ground beyond Goswell Street, near Mount Mill, being some of the remains of the old lines or fortifications of the city”.

Whilst the fort has long gone, it is known that one of the fort’s bastions stood at the junction of the modern Sebastian Street and Goswell Road (a mound in this location is clearly pictured on John Rocque’s map of 1746-7). Thanks to investigations during the 1970s and 1980s, it is known that Southampton Fort (close to the current British Museum) had a frontage of 125 metres.

In 1999, the site of the windmill itself was excavated to the north of Seward Street (see EXCAVATION OF A 15th-CENTURY WINDMILL MOUND IN SEWARD STREET, LONDON, EC1). Mount Mills runs close to the excavated site.


Applying the Southampton Fort dimensions to Mount Mill Fort, and positioning the fort’s north-west bastion at the junction of the modern Sebastian Street and Goswell Road, it is likely the fort occupied a site now covered by Goswell Road to the west and King Square Gardens to the north. Central Street runs about 40 metres to the fort’s eastern flank and Pear Tree Street, a few metres to the south.

Of course this can never be 100% accurate, but does indicate its likely location (GR  TQ 31851 82599).