A school has been accused of breaching data laws after it sent a 10-year-old boy home with a computer memory stick which contained sensitive information about his fellow pupils.

Carlos McSweeney, who attends the key stage two support centre in Fairlawn Road, Montpelier – a school for children with behaviour problems – was given the stick to save his artwork to take home.

When he got the stick home and showed his mother, they discovered personal details of every pupil at the school.

Staff have since been reminded of the Data Protection Act and the school is threatening to involve the police unless the family returns the stick.

Carlos, who suffers with attention-deficit hyperactivity disorder (ADHD), has been removed from the school by his family, who live in Fishponds.

Carlos's sister Jade, 22, who cares for her mother and brother, said: "About two months ago he brought back a memory stick that he had been given in class.

"He was excited to show what he had done at school but when he plugged it in it came up with all sorts of information that we should not be seeing.

"There were details of all the pupils at the school and their education history as well as addresses and phone numbers for them all – we were really shocked.

"We assumed that the school would be in touch because they should have known that information like that was missing.

"When I did tell them again they got angry and demanded we give it back and harassed us with early phone calls and then threatened us saying if we didn't give them the memory stick then they would have to send the police around to get it."

Mum Julie McSweeney added: "I have had enough and have taken Carlos out of the school. He is upset because he has friends there but I just don't believe they are looking after him."

A spokeswoman for Bristol City Council, said: "We take our responsibilities under the Data Protection Act very seriously and are concerned about this incident. Measures have been put in place to ensure that all staff are aware of the requirements to manage data appropriately."

The school has also described a decision to allow the youngster to use the image of a gun on his ID card as "regrettable". Carlos chose the image of a revolver for his card, which are used by pupils to buy sweets from the tuck shop.