A woman was reported to the police after going to the aid of a child left in a tree because it was the school's policy not to help youngsters in that situation.

Kim Barrett was passing Manor primary school, in Melksham, Wiltshire, when she saw a five-year-old boy apparently stuck in a tree. She went to help him but next day received a visit from a police community support officer, who told her she had been trespassing, she said.

Manor primary school today admitted that its policy was to observe children who climb into trees from a distance rather than go to them, for fear the pupil might be distracted and fall, or feel rewarded for bad behaviour.

It claimed the incident was shortlived and urged adults not to enter school grounds without permission.

Barrett, who has a six-year-old daughter at a different school, today said she was shocked by the policy. She had simply wanted to help the boy and was upset at how the school had responded.

She added that the incident had happened this month as she walked home. She went to the front of the school and on to the playing field to help the child.

Barrett, who works as a part-time cleaner, claimed the boy was in the tree for 45 minutes. The school insisted it was less than 10.

Later that evening a letter from the headteacher, Beverley Martin, was posted through Barrett's door, saying that the school had contacted the police about the incident. The next morning Barrett was visited by a police community support officer, who told her she had committed a trespassing offence.

Barrett said: "I felt really angry because I felt I had saved the school and this boy from something that could have been far worse, and that instead of thanking me I was under investigation. It was ridiculous. He was all on his own."

The school disputes Barrett's observation of the incident. It concedes that the child had been in the tree but says he got down before she reached him. It also claims Barrett climbed over a padlocked gate to get into the school.

The child had been viewed from three vantage points, the school added. In a statement it said: "The safety of our pupils is our priority and we would like to make it clear that this child was being observed at all times during this very short incident. Like other schools whose premises include wooded areas, our policy when a child climbs a tree is for staff to observe the situation from a distance so the child does not get distracted and fall. This also ensures children are not 'rewarded' with attention for inappropriate behaviour.

"Ofsted are aware of our policies and procedures and graded us as outstanding for our care, guidance and support of our children. With regard to this incident, the child's mother is in agreement with, and fully supportive of, our actions both prior to the incident and since."