A new Thames crossing will still be needed even if electronic charging is introduced at the Dartford crossing.

At least that's what transport minister Mike Penning has told the House of Commons.

Mr Penning, under-secretary of state for transport, argued that even with free-flow tolling there would be queues at the crossing.

He said: "Even with free-flow tolling at Dartford, the northern approach to the tunnels will still be congested, even according to the predictions we have now.

"The small bore tunnel has a huge restriction.

"We need to look at having another Thames crossing for this piece of national - repeat, national - infrastructure."

Mr Penning admitted the booths were "an archaic method" of collecting tolls but said this was because of the "success" of the M25.

He argued this meant another crossing over the Thames was needed.

His comments came in response to questions by John Baron, MP for Basildon and Billericay, who suggested automatic number plate recognition technology should be tried at the Dartford tolls first to see if it eases congestion before an increase in tolls is raised to fund a second crossing.

In a consultation document into plans for an increase in the Dartford toll charges - set to go up by 50p to £2 by the end of this year - it is said the rise would go towards paying for a lower Thames crossing.

In September, the KM Group submitted a petition against the toll rises to the Department for Transport as part of a public consultation into the proposed hikes.

One option, backed by Kent County Council, is for a tunnel to be built to the east of Gravesend.

No date has been released for when the hikes will take place nor for when feedback on the consultation will be given.