The Dartford Crossing has seen its revenues shrink significantly during the pandemic as travel restrictions capped the number of journeys.

It comes after a marked fall in motorists using the two tunnels and the Queen Elizabeth II Bridge since the first lockdown in 2020.

National Highways has revealed its coffers have taken a hit as traffic volumes between Kent and Essex fell by a quarter (25.5%).

Latest accounts for the year ended March 31 2021, show income generated from the river Crossing, which uses a free-flow charging system known as the Dart Charge, decreased by £47.6m to £161.4m.

The government-owned company, formerly known as Highways England, said this was in large part due to the lockdown restrictions.

The significant drop in traffic resulted in a 28% fall in penalty charge notices (PCNs) issued to drivers who failed to make a payment within the required timescale.

However, despite this fall in activity the operators of the Dart Charge continued to rake in more than a third of its income through fines.

Last year PCNs were valued and recognised at £58.7m – a £14.2m reduction on the previous period.

It was also revealed £17.4m was not picked up on the books as fines despite contraventions being recorded.

Highways bosses say fines may have not been issued to road users for various reasons.

These include the vehicle owner's details not being available, illegal activity such as cloned cars, poor vehicle images, misread number plates, issues with the system, errors made by the service provider, and discretionary action.

National Highways says system issues and errors are addressed on an ongoing basis.

However, the transport body hastens to add the vast majority of potential fines not collected were likely first time offenders who would have been offered the chance to pay the charge within 14 days, resulting in no fine being issued.

Taking this into account, it predicts actual PCN revenue loss is significantly lower than the £17.4m recorded and is more likely to be between £0.1m and £1.6m.

According to the motorway improvement agency more than 94.8% of drivers using the Dartford Crossing are paying their Dart Charge correctly and on time.

Last year we reported how journeys across the Crossing had more than halved since the first national lockdown.

But National Highways says since government restrictions were eased in June 2021 traffic volumes have increased significantly and are now more or less back to the same levels recorded pre-pandemic.

And while "Covid-19 and Brexit variables" remain, it expects traffic to stay roughly the same despite increased home working.

The government-owned company says it is not concerned about its financial position and fully expects revenues to return to levels recorded pre-pandemic.

The toll booths were scrapped in 2014 and replaced with a "free-flow charge regime".

Fees were originally meant to be scrapped after the debt of the construction of the bridge was repaid yet years down the line it still remains with cars paying £2.50 and larger vehicles up to £6 for each journey.

Currently motorists can pay the charge online, by phone and at various retail outlets, prior to or up to the day after using the crossing.

National Highways says there are not currently any plans to increase the charge.

A spokesman for the government-owned company said: "The Dart Charge has removed a significant source of congestion at the Dartford Crossing by removing the need to stop at a barrier to pay the crossing charge.

"It provides drivers with greater flexibility around options for how and when they pay.

“With more than 50 million vehicles travelling over the Dartford Crossing every year, the charge is vital to managing traffic demand which currently outstrips the capacity of the bridge crossing.

"All revenue from the crossing is passed on in full to the government and by law can only be spent on transport improvements."

But drivers often report being trapped in gridlock traffic on the crossing during busy periods and in the event of an accident.

The local council, residents and environmental campaigners have also called for more of the cash generated to be set aside for much needed road improvements.

Motorists have also hit out at its past history of technical faults and glitches which included a decision to automatically close "inactive accounts".

The policy allowed the operators to close Dart Charge accounts where there had been no activity for 12 months and led to more than £1 million of driver's funds being held.

Last year it was announced French company emovis has struck a 10-year deal worth up to £270million to continue operating the Dart Charge system.