Fortifications of London - AbsoluteAstronomy.com

The fortifications of London are extensive and mostly well maintained, though many of the City of London

City of London

The City of London is a small area within Greater London, England. It is the historic core of London around which the modern conurbation grew and has held city status since time immemorial. The City’s boundaries have remained almost unchanged since the Middle Ages, and it is now only a tiny part of...

's fortifications and defences were dismantled in the 17th and 18th century. Many of those that remain are tourist attractions, most notably the Tower of London

Tower of London

Her Majesty's Royal Palace and Fortress, more commonly known as the Tower of London, is a historic castle on the north bank of the River Thames in central London, England. It lies within the London Borough of Tower Hamlets, separated from the eastern edge of the City of London by the open space...

Roman times

London's first defensive wall was built by the Romans

Ancient Rome

Ancient Rome was a thriving civilization that grew on the Italian Peninsula as early as the 8th century BC. Located along the Mediterranean Sea and centered on the city of Rome, it expanded to one of the largest empires in the ancient world....

around 200 AD, 150 years after the city was founded as Londinium

Londinium

The city of London was established by the Romans around AD 43. It served as a major imperial commercial centre until its abandonment during the 5th century.-Origins and language:...

.
This wall

London Wall

London Wall was the defensive wall first built by the Romans around Londinium, their strategically important port town on the River Thames in what is now the United Kingdom, and subsequently maintained until the 18th century. It is now the name of a road in the City of London running along part of...

remained in active use as a fortification for over 1,000 years afterwards, defending London against raiding Saxons in 457 and surviving into Medieval times.
There were six main entrances through the wall into the City, five built by the Romans at different times in their occupation of London.
These were, going clockwise from Ludgate in the west to Aldgate in the east: Ludgate

Ludgate

Ludgate was the westernmost gate in London Wall. The name survives in Ludgate Hill, an eastward continuation of Fleet Street, and Ludgate Circus.-Etymology:...

, Newgate

Newgate

Newgate at the west end of Newgate Street was one of the historic seven gates of London Wall round the City of London and one of the six which date back to Roman times. From it a Roman road led west to Silchester...

, Aldersgate

Aldersgate

Aldersgate was a gate in the London Wall in the City of London, which has given its name to a ward and Aldersgate Street, a road leading north from the site of the gate, towards Clerkenwell in the London Borough of Islington.-History:...

, Cripplegate

Cripplegate

Cripplegate was a city gate in the London Wall and a name for the region of the City of London outside the gate. The area was almost entirely destroyed by bombing in World War II and today is the site of the Barbican Estate and Barbican Centre...

, Bishopsgate

Bishopsgate

Bishopsgate is a road and ward in the northeast part of the City of London, extending north from Gracechurch Street to Norton Folgate. It is named after one of the original seven gates in London Wall...

and Aldgate

Aldgate

Aldgate was the eastern most gateway through London Wall leading from the City of London to Whitechapel and the east end of London. Aldgate gives its name to a ward of the City...

. A seventh, Moorgate

Moorgate

Moorgate was a postern in the London Wall originally built by the Romans. It was turned into a gate in the 15th century. Though the gate was demolished in 1762, the name survives as a major street in the City of London...

, was added in Medieval times between Cripplegate and Bishopsgate.

Middle ages

After the Norman conquest

Norman conquest of England

The Norman conquest of England began on 28 September 1066 with the invasion of England by William, Duke of Normandy. William became known as William the Conqueror after his victory at the Battle of Hastings on 14 October 1066, defeating King Harold II of England...

in 1066 the city fortifications were added to, as much to protect the Normans

Normans

The Normans were the people who gave their name to Normandy, a region in northern France. They were descended from Norse Viking conquerors of the territory and the native population of Frankish and Gallo-Roman stock...

from the people of the City of London as to protect London from outside invaders.
King William

William I of England

William I , also known as William the Conqueror , was the first Norman King of England from Christmas 1066 until his death. He was also Duke of Normandy from 3 July 1035 until his death, under the name William II...

had two fortifications built:
The White Tower

White Tower (Tower of London)

The White Tower is a central tower, the old keep, at the Tower of London.-History:The castle which later became known as the Tower of London was built by William the Conqueror in 1066. It began as a timber fortification enclosed by a palisade. In the next decade work began on the White Tower, the...

, the first part of the Tower of London

Tower of London

to be built, was constructed in 1078 to the east of the city, between Aldgate and the river Thames; and Baynard's Castle

Baynard's Castle

Baynard's Castle refers to buildings on two neighbouring sites in London, between where Blackfriars station and St Paul's Cathedral now stand. The first was a Norman fortification constructed by Ralph Baynard and demolished by King John in 1213. The second was a medieval palace built a short...

, to the south west next to the River Fleet

River Fleet

The River Fleet is the largest of London's subterranean rivers. Its two headwaters are two streams on Hampstead Heath; each is now dammed into a series of ponds made in the 18th century, the Hampstead Ponds and the Highgate Ponds. At the south edge of Hampstead Heath these two streams flow...

.
A third fortification, Montfichet's Castle

Montfichet's Castle

Montfichet's Tower was a Norman fortress on Ludgate Hill in London, between where St Paul's Cathedral and City Thameslink railway station now stand. First documented in the 1130s, it was probably built in the late 11th century...

, was built to the north west by Gilbert de Monfichet, a native of Rouen

Rouen

Rouen , in northern France on the River Seine, is the capital of the Haute-Normandie region and the historic capital city of Normandy. Once one of the largest and most prosperous cities of medieval Europe , it was the seat of the Exchequer of Normandy in the Middle Ages...

, and relative of William’s.

Later in the medieval period the walls were redeveloped with the addition of crenellations, more gates and further bastions.

City gates

The 'gates' that once guarded the entrances to the City of London through the City Wall were multi-storey buildings that had one or two archways through the middle for traffic, protected by gates and portcullis

Portcullis

A portcullis is a latticed grille made of wood, metal, fibreglass or a combination of the three. Portcullises fortified the entrances to many medieval castles, acting as a last line of defence during time of attack or siege...

es. They were often used as prisons, or used to display executed criminals to passers-by. Beheaded traitors often had their head stuck on a spike on London Bridge

London Bridge

London Bridge is a bridge over the River Thames, connecting the City of London and Southwark, in central London. Situated between Cannon Street Railway Bridge and Tower Bridge, it forms the western end of the Pool of London...

, then their body quartered and spread among the gates.

After the curfew, rung by the bells of St Mary le Bow and other churches at nine o'clock, or dusk, (whichever came earlier) the gates were shut. They reopened at sunrise, or six o'clock the next morning, whichever came later. Entry was forbidden during these times, and citizens inside the gates were required to remain in their homes. The gates were also used as checkpoints, to check people entering the City, and to collect any tolls that were being charged for the upkeep of the wall, or any other purpose that might require money. It is possible that the wall was maintained for the sole purpose of collecting taxes, and not for defence at all.

The gates were repaired and rebuilt many times. After the restoration of the monarchy in 1660 all of the City gates were unhinged and had their portcullises wedged open, rendering them defenceless, but they were retained as a visible sign of the prestige of the City. Most of the gates were demolished around 1760 due to traffic congestion.

The positions of all the gates are now marked by a main road with the same name, except for Cripplegate, which is a tiny street somewhat north of the position of the gate.

17th century

Lines of Communication
Lines of Communication (London)
The Lines of Communication were English Civil War fortifications commissioned by Parliament and built around London between 1642 and 1643 to protect the capital from attack by the Royalist armies of Charles I.In 1642 some basic fortifications were built, in the form of street barricades and small...

were English Civil War
English Civil War
The English Civil War was a series of armed conflicts and political machinations between Parliamentarians and Royalists...

fortifications commissioned by Parliament and built around London between 1642 and 1643 to protect the capital from attack by the Royalist armies of Charles I. By 1647 the Royalist threat had receded and Parliament had them demolished.

19th century

London Defence Positions
London Defence Positions
The London Defence Positions were 19th century earthworks in the south-east of England, designed to protect London from foreign invasion landing on the south coast....

were earthworks, constructed in the 1880s, in the south-east of England, and were designed to protect London from foreign invasion landing on the south coast. They were built along a 70 mile (113 km) stretch of the North Downs from Guildford to the Darenth valley. They were quickly viewed as obsolete, and all were sold off in 1907, with the exception of Fort Halstead
Fort Halstead
Fort Halstead is a research site of Dstl, an Executive Agency of the UK Ministry of Defence. It is situated on the crest of the Kentish North Downs, overlooking the town of Sevenoaks...

, which is now the explosives research department of the Ministry of Defence
Ministry of Defence (United Kingdom)
The Ministry of Defence is the United Kingdom government department responsible for implementation of government defence policy and is the headquarters of the British Armed Forces....

.

World War I

During World War I, part of the London Defence Positions scheme was resurrected to form a stop line in the event of a German invasion. North of the Thames the line was continued to the River Lea at Broxbourne

Broxbourne

Broxbourne is a commuter town in the Broxbourne borough of Hertfordshire in the East of England with a population of 13,298 in 2001.It is located 17.1 miles north north-east of Charing Cross in London and about a mile north of Wormley and south of Hoddesdon...

and south of the Thames, it was extended to Halling, Kent

Halling, Kent

Halling is a village on the North Downs in the northern part of Kent, England, covering 7.1 square kilometres of land. Consisting of Lower Halling, Upper Halling and North Halling, it is scattered over some along the River Medway parallel to the Pilgrims' Way running over Kent.The origin of the...

, thus linking to the Chatham defences.

World War II and later

Further preparations were made for the defence of London during World War II

World War II

World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...

with the threat of invasion in 1940. These preparations comprised building shelters and fortifications against air attack in the city itself, and preparing defence positions outside the city against the possibility of land attack.

In the city the Cabinet War Rooms and the Admiralty Citadel were built to protect command and control centres, and a series of deep-level shelters

London deep-level shelters

The London deep-level shelters are eight deep-level air-raid shelters that were built under London Underground stations during World War II.-Background:...

prepared, as refuge for the general population against bombing. In June 1940 under the direction of General Edmund Ironside

Edmund Ironside, 1st Baron Ironside

Field Marshal William Edmund Ironside, 1st Baron Ironside GCB, CMG, CBE, DSO, was a British Army officer who served as Chief of the Imperial General Staff during the first year of the Second World War....

, concentric rings of anti-tank defences and pillboxes were constructed: The London Inner Keep, London Stop Line Inner (Line C), London Stop Line Central (Line B) and London Stop Line Outer (Line A)

Outer London Defence Ring

The Outer London Defence Ring was a defensive ring built around London during the early part of the Second World War. It was intended as a defence against a German invasion, and was part of a national network of similar "Stop Lines"....

. Work on these lines was halted weeks later by Ironside's successor, General Alan Brooke

Alan Brooke, 1st Viscount Alanbrooke

Field Marshal The Rt. Hon. Alan Francis Brooke, 1st Viscount Alanbrooke, KG, GCB, OM, GCVO, DSO & Bar , was a senior commander in the British Army. He was the Chief of the Imperial General Staff during the Second World War, and was promoted to Field Marshal in 1944...

, who favoured mobile warfare above static defence.

Following the end of World War II and with the advent of the Cold War

Cold War

The Cold War was the continuing state from roughly 1946 to 1991 of political conflict, military tension, proxy wars, and economic competition between the Communist World—primarily the Soviet Union and its satellite states and allies—and the powers of the Western world, primarily the United States...

era, further hardened defences were prepared in the city to protect command and control structures. A number of citadels

Military citadels under London

A number of military citadels are known to have been constructed underground in central London, dating mostly from the Second World War and the Cold War...

were improved, and new ones built, including
PINDAR,
Kingsway telephone exchange

Kingsway telephone exchange

Kingsway telephone exchange was a Cold War-era hardened telephone exchange underneath High Holborn in London.-History:The Kingsway telephone exchange was built as a deep-level shelter underneath Chancery Lane tube station in the early 1940s...

and, possibly,
Q-Whitehall, though much of this work is still regarded as secret.

Terrorism defences

London is a major terrorist target, having been subjected to repeated IRA bombings during the troubles and more recently an bombing by Muslim extremists on 7 July 2005. In the late 1980s the IRA planned a campaign to disrupt the City of London

City of London

. Two massive truckbombs were exploded in the City of London

City of London

, Baltic Exchange bomb on 10 April 1992 and just over a year later the Bishopsgate bombing. The Corporation of the City of London responded altering the layout of access roads to the city and putting in check points that can be manned when the threat level warrants it, these measures are known as the "ring of steel" a name taken from the name for more formidable defences that, at that the time, ringed the centre of Belfast

Belfast

Belfast is the capital of and largest city in Northern Ireland. By population, it is the 14th biggest city in the United Kingdom and second biggest on the island of Ireland . It is the seat of the devolved government and legislative Northern Ireland Assembly...

.

The rest of London (with the exception of obvious targets like Whitehall

Whitehall

Whitehall is a road in Westminster, in London, England. It is the main artery running north from Parliament Square, towards Charing Cross at the southern end of Trafalgar Square...

, the Palace of Westminster

Palace of Westminster

The Palace of Westminster, also known as the Houses of Parliament or Westminster Palace, is the meeting place of the two houses of the Parliament of the United Kingdom—the House of Lords and the House of Commons...

, the Royal residences, the airports and some embassies) do not have such overt protection but London is heavily monitored by CCTV, and many other landmark buildings now have concrete barriers in place to defend against truckbombs.

Roman times

Middle ages

City gates

17th century

19th century

World War I

World War II and later

Terrorism defences

See also