Channel Tunnel (1994): Linking Britain and France Under the Sea

The Channel Tunnel is a 50-kilometre railway tunnel beneath the Strait of Dover, linking Folkestone in England with Coquelles near Calais in France. Built between 1988 and 1994 and opened on 6 May 1994 by Queen Elizabeth II and President François Mitterrand, it ended Britain’s physical separation from continental Europe after nearly two centuries of failed plans. It remains one of the great engineering projects of the twentieth century, and in 1996 the American Society of Civil Engineers named it one of the seven wonders of the modern world.

Two centuries of plans

The idea of a fixed link across the Channel is old. In 1802 the French mining engineer Albert Mathieu-Favier proposed a tunnel lit by oil lamps for horse-drawn carriages, with an artificial island halfway across. In the nineteenth century the French engineer Aimé Thomé de Gamond spent decades studying the geology of the strait and designing tunnels and bridges.

The first real digging began in the 1880s. Using a boring machine designed by Colonel Frederick Beaumont and Thomas English, and promoted by the railway entrepreneur Sir Edward Watkin, workers drove pilot tunnels nearly two kilometres from each coast. The work was stopped in 1882 after the British military warned that a tunnel could let an invading army through.

A new Anglo-French project began in the 1970s, and some tunnelling was done, but the British government cancelled it in 1975 because of rising costs. Fears of invasion had faded, but the question of who would pay had not. Britain’s economic difficulties in the mid-1970s made a huge public investment hard to justify, and work stopped after only a few hundred metres of tunnel had been dug on the English side.

The treaty and the builders

In the 1980s Prime Minister Margaret Thatcher and President François Mitterrand revived the idea on condition that it would be built and financed privately. In 1986 the two governments chose a twin rail tunnel scheme proposed by a consortium that became Eurotunnel, ahead of rival plans for bridges and road tunnels. The Treaty of Canterbury, signed on 12 February 1986, set the legal framework, and Eurotunnel received a long concession to build and operate the link.

Construction was carried out by Transmanche Link, a group of ten British and French construction companies. Eleven tunnel boring machines were used, working from both sides. The tunnels follow a layer of chalk marl, a rock soft enough to cut but largely watertight, which lies about 25–75 metres below the seabed.

Building the tunnel

Tunnelling began on the British side in late 1987 and on the French side in early 1988, and most of the boring took place between 1988 and 1991. The French side, with wetter and more broken ground, used machines that could work under water pressure. Up to about 13,000 workers were employed at the peak of construction.

On 1 December 1990 the two halves of the service tunnel met under the sea. The English worker Graham Fagg and the Frenchman Philippe Cozette shook hands through the gap, a moment broadcast live on television. The rail tunnels were connected in 1991.

The work was dangerous: ten workers were killed during construction, most of them on the British side. Costs also rose sharply. The final construction cost of about £4.65 billion was roughly 80 percent more than forecast, and Eurotunnel carried a heavy debt for years.

How the tunnel works

The Channel Tunnel is really three tunnels. Two rail tunnels, each about 7.6 metres in internal diameter, carry trains in opposite directions. Between them runs a smaller service tunnel, about 4.8 metres across, used by maintenance vehicles and as a safe refuge. Cross-passages link the service tunnel to the rail tunnels roughly every 375 metres, and two undersea crossover caverns allow trains to switch between tracks so that sections can be closed for maintenance.

Moving trains push large volumes of air ahead of them, so the rail tunnels are linked by pressure-relief ducts above the service tunnel. A cooling system with chilled water pipes keeps temperatures down. The terminals at Cheriton near Folkestone and at Coquelles near Calais are where cars, coaches and lorries drive onto shuttle trains.

The excavated chalk had to go somewhere. On the English side much of it was placed behind a sea wall below Shakespeare Cliff near Dover, creating about 30 hectares of new land that is now the Samphire Hoe nature reserve. On the French side spoil was mixed with water and pumped into a lagoon behind a dam near Sangatte.

The opening

On 6 May 1994 Queen Elizabeth II and President Mitterrand officially opened the tunnel. The Queen travelled from Waterloo station in London on a Eurostar train, and the two heads of state met at the French terminal at Coquelles before travelling together by shuttle to Folkestone for a second ceremony.

Services began in stages. Freight shuttles carrying lorries started first, and the Eurostar passenger service between London, Paris and Brussels began on 14 November 1994. Le Shuttle trains carrying cars and coaches between Folkestone and Coquelles opened to the public later that year.

Consequences and legacy

The tunnel transformed travel between Britain and the continent. Eurostar made it possible to travel from central London to central Paris or Brussels in a few hours, and with the opening of the high-speed line in Kent in 2007, the London–Paris journey fell to about two and a quarter hours. Ferry and air traffic on short routes declined.

It also became a key route for trade, carrying well over a million lorries a year along with large volumes of rail freight. The tunnel was a physical expression of growing European integration in the years after the Single European Act, about two decades after the United Kingdom joined the EEC.

The project had difficulties. Fires broke out in the tunnel in 1996, 2008 and 2015, leading to long closures, though no one was killed. The operator’s finances were restructured several times, most notably in 2006–2007, when Eurotunnel was reorganised under French court protection as Groupe Eurotunnel (now Getlink). From the late 1990s, migrants seeking to reach Britain gathered near the Calais terminal, and security there became a major political issue.

By the numbers

Timeline

• 1802: Albert Mathieu-Favier proposes a tunnel for horse-drawn carriages.
• 1882: Digging of an early tunnel stops over British security fears.
• 1975: The British government cancels a second tunnel project.
• 1986, 12 February: Thatcher and Mitterrand sign the Treaty of Canterbury.
• 1987–1988: Tunnel boring begins on the British and French sides.
• 1990, 1 December: The service tunnel breaks through under the Channel.
• 1994, 6 May: Queen Elizabeth II and President Mitterrand open the tunnel.
• 1994, 14 November: Eurostar passenger services begin.

Why it matters

The Channel Tunnel physically joined Britain to the European mainland for the first time since the end of the last Ice Age, when rising seas flooded the land bridge between them. It changed how people and goods move across Europe and, almost ninety years after Louis Blériot’s flight across the Channel, brought the island and the continent closer than ever.