By Sally Chidzoy
Home affairs correspondent, BBC East
The family were stopped by an officer from the Channel Tunnel Policing Unit
A police force has apologised after a disabled child and his parents claimed they were detained at a Channel crossing point under the Terrorism Act.
Julie Maynard, of Ware, Hertfordshire, was taking a day trip to Calais through the Channel Tunnel in Folkestone, Kent.
The detective constable accused Ms Maynard and her husband Leslie Coombs of trafficking her son Joshua, 12.
Kent Police apologised and described the incident as inappropriate, unprofessional and lacking in tact.
The family was stopped by plain clothes officer from the Channel Tunnel Policing Unit on 20 February.
Ms Maynard, a legal advocate, said the officer, who failed to identify who she was, asked for the family's passports then asked "who's the boy?"
"My son is mixed race and the officer then told us, 'I believe you are child trafficking'."
When Ms Maynard asked the woman officer if she would be asked the same question if her son was white, she said the officer replied: "Are you accusing me of being a racist?"
She claimed the family were then told they were being detained under the Terrorism Act and said they were surrounded by "at least 10 police officers" who ordered them to get out of their car.
Ms Maynard was separated from her husband and son, who is autistic and has cerebral palsy, and taken to a detention room for questioning.
Ms Maynard said the woman officer told her: "It's obvious he [Joshua] has nothing to do with you".
She said officers had told the family they had powers to hold them for up to nine hours under Section 7 of the Terrorism Act, but they were released after more than two hours.
Mr Coombs said it was an "unpleasant and frightening experience".
Ms Maynard said: "More and more people are being stopped under the Terrorism Act - there's absolutely nothing in the act to stop individual officers abusing their powers.
"They have a difficult job to do in a difficult climate but their approach needs to be reasonable and not presumptive that every person is somehow guilty of a possible terrorism or criminal offence."
Kent Police said neither the couple nor the boy were placed under arrest or detained under the Terrorism Act.
The force said in a statement: "Our officer spoke to a white couple with a child of mixed race.
"There were three names on the passport and the officer made inquiries to check the child was leaving the country legally.
"The parents made a complaint for which we have apologised."
The force added that the officer in question no longer works at the Channel crossing and was in another post but the move was not connected to the incident.
Insp Helen Shaw, from Kent Police's Frontier Operations, apologised to the family in a letter.
In another letter she wrote: "Your complaint and my subsequent enquiries allowed me to identify that her (the officer's) manner had been insensitive, lacking in tact and that her conduct overall lacked the professionalism I expect.
"I wish to reassure you that your highly unsatisfactory experience was a very isolated incident."