With plans for a brand new Lower Thames Crossing between Kent and Essex halfway through public consultation, the original Dartford Tunnel is quietly marking its 55th anniversary this week.

The original Dartford Tunnel opened to traffic on November 18, 1963 and has since been used to make 1.5 billion journeys, a figure which grows by around 155,000 each day.

Although it has been added to over the years, with a second tunnel opening in May 1980 and the Queen Elizabeth II bridge opening in October 1991, the Dartford Crossing is still the only road crossing of the River Thames east of London.

Highways England is currently seeking views on proposals for a new Lower Thames Crossing, which will provide an additional route over the Thames from 2027.

It will be the largest road project since the M25 was built 30 years ago could create the UK's longest road tunnel linking Kent to Essex within 10 years.

The £6.8 billion Lower Thames Crossing could help remove 14 million vehicles from the Dartford Crossing each year when it is up and running, a new consultation on the project claims today.

The 14.5 mile tunnel will be built to the east of Gravesend and is expected to reduce traffic at Dartford by 22 per cent with 14 million fewer vehicles using it every year.

Development director for the Lower Thames Crossing David Manning, said: “At 55 years old, Dartford Crossing remains a vital piece of national infrastructure having provided decades of service to the country.

"However, being the only way to get across the Thames east of London, it carries more traffic than it was ever designed for – leading to regular delays.

"This anniversary co-insides with our public consultation for the Lower Thames Crossing, a new route across the Thames connecting Kent, Essex and Thurrock.

"We want everyone to get involved and help us shape our plans and maximise the benefits, a transformational project of this size can deliver.”

The existing Dartford Crossing is designed to carry up to 135,000 vehicles a day, although it regularly carries more than 180,000, with that number increasing every year.

Keeping it running is a 24/7 operation, and involves major maintenance and a regular inspection programme.

In recent years the two Dartford Tunnels have been fully refurbished with new lighting, ventilation and fire suppression systems that significantly improve safety standards.

Virtually all the work has been carried out overnight or at weekends, while keeping the crossing open to traffic.

Since opening, just shy of a billion vehicles had crossed Dartford by 2004. This number increased by over 50% during the following decade to 1,537,084,159.

The multi-billion pound Lower Thames Crossing would nearly double road capacity across the River Thames and almost halve the morning peak average journey times between M25 junctions 1b and 31 from nine minutes to just five.

The consultation on the latest proposals, which has already had reaction from thousands of people, aims to maximise the project’s huge benefits ends on Thursday, December 20.

Sixty events were organised between the start of the consultation on Wednesday, October 20, for people, businesses and communities to ask questions and give their views on it.

People can find out more about the public consultation and give their feedback by clicking here

History of the Dartford Crossing

1924 - The idea of a tunnel crossing the Thames was first proposed by the Ministry of Transport in 1924.

Initial reports at the start of the year suggested a crossing between Tilbury and Gravesend, replacing a ferry service, but this had been rejected by July in favour of a route further upstream, near Dartford.

1929 -The total cost of building the tunnel had been estimated at £3 million, equivalent to £167 million in 2016.

The tunnel was planned to be part of a general orbital route around London and was provisionally known as part of the South Orbital Road.

1936 - Engineering work on the tunnel begins, before being disrupted by the outbreak of World War II three years later

1959 - Construction resumes, the delay in work due to the war allowed the tunnel's design to be improved, which included a better ventilation system.

1960 - Kent and Essex county councils obtained Government approval to charge tolls when the tunnel opens. The toll was originally two shillings and sixpence, equivalent to 12.5p post-decimalisation, and about £2 in 2016.

1963 - The tunnel opened to traffic on Monday 18 November – the total project cost was £13 million (equivalent to £237 million in 2016) and it initially served around 12,000 vehicles per day.

1970 - Plans for a second tunnel are announced, after traffic volumes through the tunnel reach more than 8 million a year. The second tunnel would be built in conjunction with the North Orbital Road, later to become the M25.

1971 - Plans for the second tunnel are approved in April.

1974 - Funding for second tunnel agreed with EEC contributing to cost

1980 - The second tunnel opens to traffic in May, increasing capacity to 65,000 journeys a day. Located just to the east of the original, the new tunnel takes southbound traffic from Essex into Kent, while the original tunnel takes traffic northbound from Kent into Essex.

1982 - The Essex side of the tunnel is liked with the newly built M25 at junction 31 in May.

1986 - The Kent side of the tunnel is linked with the newly built M25 at junction 1a in September. Daily traffic volumes are now 79,000.

1988 - Construction starts on Queen Elizabeth II bridge by the Dartford River Crossing Limited, (a consortium of builder Trafalgar House (later Kvaerner), financiers Kleinwort Benson and Bank of America, and Prudential Insurance) who also finance the project and will operate the crossing for a fixed period.

1991 - The new bridge is opened by Queen Elizabeth II on 30 October. At the time of opening, it had the longest cable-stayed span of any bridge in Europe. It is the only bridge across the Thames east of central London to be opened since Tower Bridge in 1894. It increases capacity to four lanes in each direction and 135,000 vehicles per day.

2003 -Toll payments to the bridge’s construction company ceases, and revenue reverts to the Government. The toll becomes a road user charge to manage demand for the crossing, and is revenue ringfenced by law for transport.

2008 - Overnight crossing charges at the Dartford Crossing are removed.

2014 - Dart Charge is introduced at the Dartford Crossing, reducing a major source of congestion at the crossing. Instead of stopping at a barrier to pay the crossing charge drivers pay online, by phone or post or in any of thousands of local shops across the country.

2016 - A consultation is held on proposals for a new Lower Thames Crossing.