[22][23][24] In 1802, Albert Mathieu-Favier, a French mining engineer, proposed a tunnel under the English Channel, with illumination from oil lamps, horse-drawn coaches, and an artificial island positioned mid-Channel for changing horses.

After the surrender of France, as Britain prepared for an expected German invasion, a Royal Navy officer in the Directorate of Miscellaneous Weapons Development calculated that Hitler could use slave labour to build two Channel tunnels in 18 months.

[15] Public opinion strongly favoured a drive-through tunnel, but concerns about ventilation, accident management and driver mesmerisation resulted in the only shortlisted rail submission, CTG/F-M, being awarded the project in January 1986.

The Treaty of Canterbury (1986) prepared the Concession for the construction and operation of the Fixed Link by privately owned companies and outlined arbitration methods to be used in the event of disputes.

[63] The tunnel was officially opened, one year later than originally planned, by the French president François Mitterrand and Queen Elizabeth II, at a ceremony in Calais on 6 May 1994.

The English terminal had to be located in the Castle Hill landslip, which consists of displaced and tipping blocks of lower chalk, glauconitic marl and gault debris.

[80] The service tunnel acted as a pilot preceding the main ones, so that the geology, areas of crushed rock, and zones of high water inflow could be predicted.

[80] Marine soundings and samplings were made by Thomé de Gamond in 1833–67, establishing the seabed depth at a maximum of 55 m (180 ft) and the continuity of geological strata (layers).

On the English side, a marshalling area was 140 m (459 ft) below the top of Shakespeare Cliff, the New Austrian Tunnelling method (NATM) was first applied in the chalk marl here.

[clarification needed] Owing to limited space, the precast lining factory was on the Isle of Grain in the Thames estuary,[82] which used Scottish granite aggregate delivered by ship from the Foster Yeoman coastal super quarry at Glensanda in Loch Linnhe on the west coast of Scotland.

The eleven tunnel boring machines were designed and manufactured through a joint venture between the Robbins Company of Kent, Washington, United States; Markham & Co. of Chesterfield, England; and Kawasaki Heavy Industries of Japan.

[96] The traditional railway south of London uses a 750 V DC third rail to deliver electricity, but since the opening of High Speed 1 there is no longer any need for tunnel trains to use it.

Reinforced concrete blocks of 100 kg (220 lb) support the rails every 60 cm (23.6 in) and are held by 12 mm (0.47 in) thick closed-cell polymer foam pads placed at the bottom of rubber boots.

Twin fans are mounted in vertical shafts where digging for the tunnel began, on both sides of the channel: two in Sangatte, France, and two more at Shakespeare Cliff, UK.

At the end of 2009, extensive fire-proofing requirements were dropped and DB received permission to run German Intercity-Express (ICE) test trains through the tunnel.

[110][111] In October 2021, Renfe, the Spanish state railway company, expressed interest in operating a cross-Channel route between Paris and London using some of their existing trains with the intention of competing with Eurostar.

[118] Although the captured share of Channel crossings was forecast correctly, high competition (especially from budget airlines which expanded rapidly in the 1990s and 2000s) and reduced tariffs led to low revenue.

The terminals are organised with the frontier controls juxtaposed with the entry to the system to allow travellers to go onto the motorway at the destination country immediately after leaving the shuttle.

Some small-medium enterprises located in the immediate vicinity of the terminal have used the opportunity to re-brand the profile of their business with positive effects, such as The New Inn at Etchinghill which was able to commercially exploit its unique selling point as being 'the closest pub to the Channel Tunnel'.

By 1997, the problem had attracted international press attention, and by 1999, the French Red Cross opened the first migrant centre at Sangatte, using a warehouse once used for tunnel construction; by 2002, it housed up to 1,500 people at a time, most of them trying to get to the UK.

[168] Approximately 3,000 migrants, mainly from Ethiopia, Eritrea, Sudan and Afghanistan, were living in the temporary camps erected in Calais at the time of an official count in July 2015.

The French government built a double fence, at a cost of £5 million, reducing the numbers of migrants detected each week reaching Britain on goods trains from 250 to almost none.

[180][181] On 23 and 30 June 2015,[182] striking workers associated with MyFerryLink damaged sections of track by burning car tires, cancelling all trains and creating a backlog of vehicles.

[166] In the two months from June to July 2015, ten migrants died near the French tunnel terminal, during a period when 1,500 attempts to evade security precautions were being made each day.

On 9 December 1994, during an "invitation only" testing phase, a fire broke out in a Ford Escort car while its owner was loading it onto the upper deck of a tourist shuttle.

[211] Nirj Deva, Member of the European Parliament for South East England, had called for Eurostar chief executive Richard Brown to resign over the incidents.

[212] An independent report by Christopher Garnett (former CEO of Great North Eastern Railway) and Claude Gressier (a French transport expert) on the 18/19 December 2009 incidents was issued in February 2010, making 21 recommendations.

The design limit was set at 30 °C (86 °F), using a mechanical cooling system with refrigeration plants on both sides that run chilled water circulating in pipes within the tunnel.

Two STTS (Service Tunnel Transportation System)[223] vehicles with firefighting pods are on duty at all times, with a maximum delay of 10 minutes before they reach a burning train.

In 2009, former F1 racing champion John Surtees drove a Ginetta G50 EV electric sports car prototype from England to France, using the service tunnel, as part of a charity event.