Highways England has indicated road users will be charged to use a new tunnel under the Thames – but stalled on revealing the likely width of roads in each direction.

Although its consultation on the Lower Thames Crossing is focused on selecting the right route for traffic heading between Kent and Essex, the authority indicated government policy is to charge for such infrastructure projects.

However, it has remained tight lipped about the width of roads entering the tunnel.

Images released as part of the consultation show two lane traffic travelling either side.

Yet this would connect with the four-lane M2, potentially creating a bottleneck and negating any economic benefits.

“It is a very good point,” said Natalie Chapman, the Freight Transport Association’s head of policy for London and the South East.

“We need to look carefully at the DfT modelling behind this to see what the expected level of demand is.

“We want to build infrastructure for future needs. We don’t want to put in two lanes and soon have to start building again because demand means we should have had three or four.

“More lanes added in now will increase the cost but if we need more capacity it could cost even more in the longer term.”

Ms Chapman added that FTA members expected to have to pay for the Lower Thames Crossing but said she would “love to see those charges scrapped as we were promised in 2003”.

She said: “We understand new infrastructure comes with a heavy price tag.”

Highways England spokesperson Sarah Silk said: “Government policy is to levy a charge for estuarial crossings. However, it is too early at this stage to confirm.

“I do want to stress that the consultation at this stage is about finding the best route.”

Regarding the width of the roads, she said: “We’re not that far yet and that is why we’re holding the consultation and welcome views.”