AN engineering and transport expert whose portfolio of work includes iconic transport links including France's Millau Viaduct says a rethink of the Lower Thames Crossing project should take place and the scheme should include a rail link.

Alistair Lenczner is a world-renowned expert who worked on many major engineering projects with Foster + Partners and is now a director of multi award-winning engineering consultancy.

Mr Lenczner's input on projects has been known to result in multi-million pound cost savings through simplified construction logistics and, following Highways England's decision to pull its Lower Thames Crossing development consent planning application last November he has spoken up to say it is time for a rethink of the whole project.

He believes infrastructure projects like the Lower Thames Crossing should be "multi-purpose" and span more than one sector and the crossing should be redesigned to include a road and railway.

He added that this would help improve the project's benefits and reduce its carbon impact.

"No one thinks about integrated projects and this is a perfect example where there is a clear opportunity and a clear benefit," he told the New Civil Engineer magazine: "We need to think of a complete picture of national infrastructure."

He says roads, railways, airports, energy and water, for example, are currently planned and delivered by separate agencies, with none responsible for identifying opportunities for multi-purpose projects that could deliver benefits across two or more sectors.

"It's a complete blind spot and opportunities are being missed," Mr Lenczner said.

Highways England pulled its Lower Thames Crossing planning application last month after the Planning Inspectorate asked for more information about construction plans and the predicted ecological and environmental impact of the scheme.

The project will connect Thurrock with North Kent with two 4.2km long road tunnels, and it is being created to alleviate congestion on the Dartford Crossing. Its development consent order application is expected to be resubmitted in the coming months by Mr Lenczner says the delay has created an opportunity.

Since the planning application was pulled, Highways England figures released under the Freedom of Information Act have revealed that the project will emit 2M.t of greenhouse gas into the atmosphere and that traffic created by the road tunnel will generate another 3.2M.t over 60 years.

Mr Lenczner said that redesigning the scheme to include a railway would reduce its carbon impact and provide a "valuable new link" in the national rail network.

He likened the concept to the Fehmarnbelt road and rail link being built between Germany and Denmark, and added that a railway would strengthen the links between Kent and Essex and give ports such as London Gateway, Tilbury and Felixstowe better rail access to the UK and Europe.

Mr Lenczner said he simply wants "to put the challenge out there" to see if others think it could be worthwhile to combine projects to harness multiple benefits.

"The technical solutions are there," he said. "We need the agencies set up so they can identify the solutions and we need the legal and regulatory set up to allow them to proceed so they can get funded."

Mr Lenczner added: "If you do a road tunnel first, futureproof it so you can add a railway later. It doesn't always have to be all done in one big bang.

"You can design infrastructure so components can be added over time. You think forward and anticipate what might happen over the next 10 or 20 years."

A Highways England spokesperson said: "A detailed analysis undertaken by the Department for Transport in 2009 found that including a rail link, for passenger and freight, would not provide value for money due to a significant number of technical challenges and it wouldn't have provided an effective solution to the problems at Dartford."