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 has been given a number of new features since the Government chose to build the route to the east of Gravesend in April last year.

What the Lower Thames Crossing could look like

Most notably, the crossing will be a three-lane dual carriageway in both directions, having previously been planned as two-lanes.

The second consultation, which launches today and is due to run for 10 weeks, also features plans to build a service area in Tilbury and an improved junction with the A2.

Motorists are likely to have to pay to use the route, with work expected to start in spring of 2022.

The aim is for the crossing, which will link Gravesend to Thurrock, to open in 2027.

The first consultation on the project attracted 47,000 responses, which was a record for a UK road scheme.

However, it was marred by accusations from some camapaigners that much of the opposition to the project was hidden after Highways England lumped together 13,000 people as just 14 responses.

The latest plans include extending the tunnel by 600 metres to protect access to a community church and reduce the visual impact.

It will also be lowered by up to six metres and be moved 80 metres further east, where it passes Chadwell St Mary in Thurrock, to increase the distance from residential properties.

These changes mean the expected sum to be spent on the project is now between £5.3 billion and £6.8 billion.

The 14.5-mile route is expected to reduce traffic at Dartford by 22% with 14 million fewer vehicles using the crossing every year.

Highways England project director Tim Jones

Developers want to hear the public’s views on introducing a charge to use the crossing, similar to the Dart Charge.

Highways England's project director for Lower Thames Crossing, Tim Jones, said: “It’s been hard work over the last 18 months since the secretary of state announced the preferred route.

“We have had to make sure that the project going out really has been designed very, very well if we’re going to keep to the timetable and make sure we have enough time to hear people’s concerns.

“There needs to be a conversation happening. We want to hear what people feel about charges and we are asking about their views on variable charging.

“For too long the Dartford Crossing has been the only way to get across the Thames east of London.

“The Lower Thames Crossing is the most ambitious project of its kind ever in the UK and the biggest single road upgrade since the M25 was completed more than 30 years ago.

“It would almost double road capacity across the Thames cutting congestion, significantly easing pressure at the Dartford Crossing and boosting the resilience of the whole road network.”

Many businesses in Kent believe the new crossing is essential to keeping trade moving after Britain leaves the EU.

Port of Dover head of policy and communications Richard Christian said: “The UK’s reliance upon continued frictionless trade at the Port of Dover has been accepted at the heart of Government.

"So has the need to preserve it. For a port handling £122bn or 17% of the UK’s trade in goods, and with half of that trade moving beyond London to keep factories busy and shops full in the Midlands and the North, the Lower Thames Crossing is an investment in the long-term economic success of the UK as a whole.

"The port continues to press hard for a Government commitment to other complementary strategic investments such as the dualling of the A2 to Dover which, together with the Lower Thames Crossing, will help protect jobs and livelihoods, keep traffic flowing and prices low for British consumers.”

Jo James, chief executive of Kent Invicta Chamber of Commerce, said: “The Lower Thames Crossing will open up new opportunities, enabling businesses across Kent and the wider South East to achieve their growth potential and will have a significant impact on our future prosperity.

“As the 10-week consultation opens, I would strongly urge businesses to put their views forward by responding to the consultation.”

Planning permission, in the form of a development consent order, will be put forward next year.

Leader of Medway Council, Cllr Alan Jarrett (Con), said: “We fully support the proposal for an additional crossing and investment in the wider road network.

"A Lower Thames Crossing will not only reduce congestion on the Dartford Crossing, but it will also bring with it economic benefits to both sides of the river; it will bring more visitors into the south-east and would benefit commuters.

“Medway is fast becoming known as the new economic powerhouse for the south-east, and although we already have great transport connections, such as a high speed rail service into central London, a new crossing will be a major catalyst to drive further economic development.

“We will be submitting a response to Highways England’s consultation and would encourage residents and businesses to attend a consultation event to find out more about the proposal and how the crossing would affect them, as well as provide their feedback.”

For full details of where public consultation events are taking place and how to take part click here.