Peterborough City Council have apologised after sending confidential medical documents about a pupil to the wrong family.
The documents were received by the family on Christmas Eve. They were included in a pack of documents about their own son.
The stepdad of the boy said he was shocked by the data breach - and would be furious if documents relating to his child had been sent out wrongly.
Now Peterborough City Council has started an investigation into how the documents were mistakenly sent to the wrong family.
They have also apologised to both parties.
The stepdad, who asked not to be named said: “My stepson gets extra help at school, and gets a ‘statement’ from the council.
“We received the documents on Christmas Eve, and in the envelope were about 10 extra confidential documents relating to another child. We could not believe it.
“We phoned the council straight away, and were asked to shred the documents. I said I would not do that, as it should be done by a proper firm.
“The council then came and picked the documents up.
“This sort of thing really should not happen. It is a data breach.
“If documents about my stepson had been sent elsewhere, I would be furious. We were told it was just a mistake, but these things should never happen.”
A Peterborough City Council spokesman said the investigation would try and find ways to prevent similar errors happening again in the future.
The spokesman said: “We take all breaches of data very seriously and thoroughly investigate every case.
“Immediate action was taken as soon as we were alerted and an officer visited the recipient to retrieve the documents sent in error.
“We have been in touch with both parties to offer an unreserved apology.
“We are now in the process of conducting an investigation to ensure that a similar incident does not happen again in the future.”