The City of London is in an area that has no indigenous building stone; its underlying layers of sand, gravel and clay are poorly consolidated materials that are not suitable for use as building stones.
Despite this, stone has been used as a major construction material in London since Roman times.
The building stones of London takes you on a journey from AD 200 to the present explaining what materials were used in some of London's great buildings:
London’s status as a capital city dates from Roman times, but earlier settlements developed principally because of their riverside location on a major trade route.
One of the few substantial early stone structures that is still visible above ground is the impressive remnants of the defensive walls, built principally of Kentish Ragstone (Lower Cretaceous), that protected the Roman city.
Archaeological digs, however, regularly reveal evidence of a wide range of other stone-built structures, essential to the development of any Roman city.
An amphitheatre, basilica, forum, temple, villas, bath houses, and stone quaysides have all been revealed under present-day London. Consequently, like many other capital cities of the world London has had to rely for the whole of its history on importing of building stone from further afield.
The River Thames remained the principal means of access to the growing city for the transport of building stone up until the development of the railway network in the early 19th century.
Such early stone structures show a variety of stone types. Most common are the sandy limestones of the Kentish Ragstone (Hythe Formation) sourced from extensive quarries around Maidstone in Kent; flint nodules (Upper Cretaceous) from the Chalk of the Downs or reworked into the river-borne gravels of the Thames.
Fragments of Purbeck Marble — as tombstones — (Dorset), Lincolnshire Limestone, White Lias limestone (Cotswolds), Welsh Slate, black Tournai (Belgian), white Carrera (Italy) and other coloured marbles, together with Egyptian and Greek porphyritic igneous rocks, discovered at many sites suggest, not only a growing knowledge of Britain’s own building stone resources, but also that a thriving trade in building stone was already underway with the rest of the Roman Empire.
The Normans, after 1066, introduced both new masonry skills and new stones into the city.
The extensive use of Caen Stone (Middle Jurassic limestone), sourced from underground quarries in Normandy, is one notable import, which probably reflects as much on the poor state of the overland communications routes between London and its provinces, as on the quality of the limestone itself, which did not prove to be very durable.
The first priority of William I was defence, and the White Tower (of London, c.1078–1097) was one of several castles constructed in the city. The principal stones used were Kentish Rag rubblestone, with Caen (France) and Quarr (Isle of Wight, Palaeogene) limestones from France, and Reigate Stone (Upper Greensand, Surrey) sandstone dressings.
The medieval reconstruction of Westminster Abbey (originally built, it is believed, of Reigate Stone), for example, used Caen, Kentish Rag, Reigate and Clunch (Upper Cretaceous Chalk, Cambridgeshire), together with the ubiquitous decorative columns of fossiliferous Purbeck Marble (Upper Jurassic).
With the exception of Reigate ‘freestone’, which was carried overland, the other stones were brought in by sea and river. The façade we see today of the Abbey has, however, been largely re-faced in white Portland (Upper Jurassic) and yellow Bath (Middle Jurassic) limestones (Somerset).
Similarly the Guildhall (Kentish Ragstone) which possesses the largest and most spectacular Collyweston Stone (Middle Jurassic, Northamptonshire) slate roof in the country, is of medieval origin, but has been largely rebuilt, at least above ground level, since that time.
The Guildhall's roof is a recent replacement following fire damage during the Second World War.
Buckingham Palace originally constructed principally of Caen limestone has been refaced with Bath Stone.
Changes in building styles and materials over two millennia have been frequent in London and were often driven by events outside the city, most notably the Roman and Norman invasions.
However, in 1666 a more local catastrophe, the Great Fire, lead to a fundamental change to the face of London’s buildings. Medieval London was a place of narrow streets and timber-framed houses, and the fire destroyed thousands of such properties.
However, one of the ‘benefits’ was that in the aftermath a raft of legislation was introduced to ensure that such devastation could not happen again. The new legislation required streets to become wider and straighter, new buildings to be built principally in brick or stone and to ensure roofs were no longer of thatch.
Before the fire white Portland limestone (Dorset) was a comparative rarity in the city’s buildings, although Inigo Jones had first used the stone for the Banqueting House (1619–22), part of the never completed Palace of Whitehall.
The need for rebuilding on a vast scale required a massive expansion in local brick production (London Clay Formation) but Portland Stone became the material of choice for buildings of consequence.
Using this white limestone Wren, Hawksmoor and Vanbrugh began to transform the devastated face of London by the construction of 51 new churches to replace those destroyed in the Great fire.
In the 18th century came a further transformation of the city’s stone architecture.
The Georgian city corporation and local aristocracy, through their patronage of the new ‘Palladian’ architectural style, commissioned many new classically styled buildings — Burlington House, the British Museum, Somerset House, the Bank of England and the Mansion House are all constructed of Portland Stone and grey Cornish granite.
An exception, however, is Chandos House constructed instead of grey Craigleith (Carboniferous) sandstone from quarries in Edinburgh.
It was not until the 19th century that we see a move away from the almost exclusive use of Portland Stone for all the important new buildings in London.
The city’s growing wealth from the proceeds of its overseas empire encouraged its continuing development as a major port. New quay and docksides were built with Cornish and Scottish granites and Yorkshire sandstones (Jurassic and Carboniferous). Tower Bridge was constructed using Cheesewring granite from (Cornwall).
The gradual arrival of the mainline railways into London from every corner of the country, opened up markets for stone from other sources. These new (to London, at least) stone resources could now readily compete with the Portland quarries which had no suitable rail link.
The railway companies advertised their success with a series of new railway stations and luxurious hotels such as St Pancras Station.
This increasing choice of building materials is exemplified in the early 19th century by the construction of the New Houses of Parliament. Following a disastrous fire in 1834 much of the old Palace of Westminster was destroyed.
A competition was organised by the government between the country’s leading architects to produce a suitable design for this most prestigious of buildings.
Having chosen the design, which was eventually developed into the buildings we see today, it was then decided to set up a Commission to examine and select a suitable building material for its construction.
Having completed their task by examining over 100 stone quarries, throughout the length and breadth of Britain, the architect and commissioners selected a pale yellow limestone (Magnesian Limestone, Permian) for the building.
After several false starts the building (1839–1852) was principally constructed using magnesian limestone from the Anston Quarries in South Yorkshire.
However, from an early stage the stone proved to be unsuitable for the increasingly smoke-polluted atmosphere of urban London and decay became a serious problem.
As a consequence, since its construction, much of the original stone has been replaced by the more durable Clipsham Stone, a pale yellow Middle Jurassic limestone from Lincolnshire.
The publication of the results of the stone survey carried out for the New Houses of Parliament broke the mould by stimulating a market for stones other than Portland in London.
By the latter part of the 19th century an architect was able to select from a colourful ‘pallet’ of stone — grey and red granites from Cornwall and Scotland; white, grey, yellow and green sandstones from the numerous Pennine quarries, and yellow and cream coloured limestones from the Jurassic of Gloucestershire, Wiltshire and Oxfordshire.
The rapidly expanding slate industries of Cornwall, Wales and Cumbria continued to provide much of the material for roofing London, and its streets were paved with flagstones from Yorkshire, Lancashire, South Wales and Caithness, a goldmine for the quarry owners of the north and Wales no doubt!
The import of stone into London is, as we have seen, nothing new. Mediterranean marbles were first imported by the Romans, and in the 19th and early 20th centuries, Victorian and Edwardian offices and churches were often clad internally with decorative marbles, serpentinites and colourful igneous rocks.
The Albert Memorial represents the pinnacle of the decorative use of indigenous British stones in any structure in London. In the memorial the architect George Gilbert Scott used 12 different varieties of stone.
In contrast, Westminster Cathedral (1895-1903) a striking mix of red brick and Portland Stone,externally is a veritable Aladdin’s cave of imported marbles (126 in all).
Occasionally, the stones found make an interesting story. Cleopatra’s Needle, an obelisk of coarse-grained, igneous syenite (an igneous rock) from the Egyptian Empire (c. 1460 BC) was belatedly brought to the city in 1878 to commemorate the defeat of Napoleon Bonaparte in 1815.
Nelson’s column, built of massive drums of grey Foggintor granite from Devon, has a Corinthian capital cast in bronze from old cannon, at the Woolwich Arsenal, with the statue itself carved from the Scottish Craigleith sandstone.
An often ignored market for stone in London is for pavement and road surfaces.
Modern macadamized surfaces in the city date from the 1850s, but prior to this granite setts and blocks were the norm. The leading producers were the granite quarries of Leicester (Charnwood), Aberdeen and Guernsey.
In the 20th and 21st centuries the market for stone has become if anything greater.
However, an architect can now choose not only from any one of the 350 or so building stone quarries that still operate in Britain, but from countless other stone sources around the world.
Today the demands of the market are, of course, very different. Pre-cast concrete structures, some dating from the beginning of the 20th century, together with steel and glass dominate the skyline in London.
Any stone used must be capable of withstanding higher mechanical stresses in more exposed locations. Many of Britain’s historic indigenous building stones are now being displaced by imported stones, where colour, size and economics are more important considerations than historic precedence and the ultimate source of stone.
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Tatton-Brown, T. 2001. The Quarrying and Distribution of Reigate Stone in the Middle Ages. Medieval Archaeology. 15, 189-201.
Worssam, B, and Tatton-Brown, T. 1993. Kentish Rag and other Kent building Stones. Archaeologia Cantiana.