It was thought to be the remedy to the nightmare that is the Dartford Crossing.

But six months after Dart Charge was launched, drivers have instead faced a vast array of errors caused by its computer system.

From being double-charged for crossings to having money pinched from motorists’ bank accounts, readers have regularly contacted the KM Group complaining of their frustrating experiences with the system.

Now, Dart Charge project director Nigel Gray has apologised for the “unanticipated” high number of problems.

He said: “I totally accept that too many people have had problems, and on behalf of Highways England I want to apologise to these people who have had issues.

“They should not have had that experience but we are working hard to put in place fixes and to give people a better customer service.

“I am not complacent about this, but it is a very high transaction business and things will happen from time to time.

“To be fair, a lot of these things are our fault, but sometimes as with all these systems, the website makes an error.

“We are experiencing more problems than we anticipated but I do think what we are experiencing is fairly typical of an IT system being introduced.

“Every day, 120,000 people use the crossing within the charging period… this is a real high volume system.”

Mr Gray put the poor performance of the Dart Charge IT system down to the fact it depended on web developers in New York.

However, on-site software developers have now been stationed at Sanef’s office in Leeds – where Dart Charge’s toll system is operated from – so any future problems will be dealt with quicker.

He added: “Since the system started, we have dealt with 20 million crossings. The vast majority of crossings have gone failry smoothly.

“So far, we have increased the number of our accounts holders.

“We have got 12,000 people that have benefited from the Local Residents’ Discount scheme.

“To be fair, a lot of these things are our fault, but sometimes as with all these systems, the website makes an error." - Nigel Gray, project director

“But I accept and recognise that some people – too many people – have had problems with trying to pay their Dart Charge accounts and trying to do things with it.”

To make matters worse for Mr Gray, it was recently revealed that one in four foreign drivers did not pay their toll during the first four months of Dart Charge’s operation.

Mr Gray said: “What these figures show is that the vast majority of drivers are paying their Dart Charge, and that non-payment is being followed up appropriately.

“We understand that Dart Charge is a significant change, and we are working hard to strike the right balance between being absolutely clear that drivers need to pay the charge, while giving people the maximum opportunity to avoid a penalty.

“It is simply not true that foreign drivers are getting off scot-free. We have enforcement arrangements across Europe, and have already passed nearly 60,000 cases to our European debt recovery agent for collection.”

Dartford MP Gareth Johnson said: “The vast majority of foreign lorry drivers behave in a perfectly lawful way.

“For the minority who try to take advantage of the system, we have given powers to the Highways Agency for them to seize lorries and for payment to be enforced against them in their own countries.

“It’s essential that the system is fair and no group of drivers is able to dodge their obligations.”

In an attempt to resolve issues Dartford residents have experiened with the Local Residents’ Discount scheme, Mr Gray revealed that surgeries have been set up to allow customers to try to solve their problems face-to-face.

He said: “When people ring our customer call centre, there is now a new option that asks people if they are signed up to the Local Residents’ Discount scheme.

“It’s dedicated to people who live in the Dartford and Thurrock areas. That will take them to a specialist adviser.

“Some of the things people are finding difficult are not necessarily that straightforward.

"What we are doing for these people is offering them face-to-face appointments. Three days every week for the immediate future we will be holding these surgeries. These started last week and so far the feedback we have had has been positive.”

The toll barriers that northbound traffic is currently having to pass through are expected to be removed by the end of July.

This is when drivers are expected to get the full benefits of the free-flow system.

Removal of these barriers will begin this month.

Among the glitches experienced was a man who had £40 taken from his account without permission after signing up for Dart Charge.

David Smith, 56, opened an account for the scheme back in December with £20, which he planned on topping up manually when it ran out.

Months later, Mr Smith found that an extra £20 had been withdrawn from his bank account and added to his Dart Charge account on two separate occasions.

He said: “The first time I noticed it I didn’t think much of it. I wasn’t happy but I figured I would use up the money eventually anyway.

“But when I noticed another £20 missing, I wasn’t having it.”

I accept and recognise that some people – too many people – have had problems with trying to pay their Dart Charge accounts and trying to do things with it" - Nigel Gray

Mr Smith rang Dart Charge customer services, run by French company Sanef, to report the issue. But after spending hours of the phone he will still have to wait up to 15 working days before Highways England respond.

Other problems that have cropped up include a Dart Charge user who was slapped with a £140 fine because the payment system failed to tell the difference between the letter ‘o’ and the number ‘0’.

Ray Hudson, 56, passed through the Dartford Crossing in December last year on a round trip to visit his elderly mother who lives in Harlow, Essex, paying his toll in advance using the PayZone system in a local newsagents.

A few weeks later, he was shocked to receive two £70 penalty notices in the post claiming that the number plate recognition system did not recognise his car.

He believes it is because his number plate contains both a number zero and a letter ‘o’, and that the data was entered wrongly into the system.

Mr Hudson, a retired construction worker from Horley, Surrey, said: “It’s ridiculous. I am surely not the only person who writes an ‘o’ the same way as an ‘0’?

“There was nothing to say that I should clearly mark which were numbers and which were letters, I just wrote it down as I usually would.”

No validation system is currently in place to pick up errors like this, despite the fact that mixing up the two figures would not fit the template for standard registration plates.

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