Highland Council’s former area roads manager Iain Wallace was travelling behind the lorry on the dual carriageway at Slochd, and could not avoid hitting the rear of the flat-bed unit.

He received serious face injuries, including a fractured eye socket, and had to be cut free from his vehicle by firefighters.

Yesterday, lorry driver Kenneth Finlayson, a former employee of Munro and Sons (Highland) Ltd, pleaded guilty to a breach of construction and use legislation regarding the lorry.

Finlayson, who did not attend court, told police at the time of the accident on November 13, 2008, that he “did not have a clue” how the trailer, loaded with two empty skips, had become detached.

The 49-year-old, of 21 Buchanan Court, Station Road, Dingwall, said he saw “sparks” in his mirror and then the trailer was gone.

Munro and Sons Ltd were also charged with offences relating to the accident, but their pleas of not guilty were accepted by the Crown.

Sheriff Peter Hammond said the accident “could have had more disastrous consequences”.

Fiscal depute Fiona Murray said that, while one motorist following Finlayson avoided hitting the trailer, Mr Wallace’s southbound car could not.

Marks found on the road showed that the trailer travelled for more than 192 yards before it stopped.

Inspectors from the Vehicle Operators and Services Agency found that the towbar was in a poor state of repair.

And a senior manager from the towbar manufacturers who studied the hitch reported that the accident was caused by poor maintenance and because the safety indicator, that would have warned of a towbar problem, was damaged.

The Traffic Commissioner for Scotland disqualified Finlayson from holding an HGV licence for 12 months in June last year.

But the court heard that he is now free to apply for the licence again, although he must resit his test.

Munro and Sons had their operators licence suspended for five years.

Duncan Henderson, representing Finlayson, said the driver was sorry for the injuries suffered by Mr Wallace.

Mr Henderson said that Mr Wallace had now raised an action at the Court of Session and was expected to claim for a six-figure sum.

He said that his client had lost his employment as a result of the Traffic Commissioner’s actions.

Mr Henderson added that several mechanics had worked on the truck in the months before the accident and none had raised any issues with the towbar and hitch.