Parents are still fuming after more than 10,000 letters were sent to children as young as seven telling them to get tested for sexually transmitted diseases.
As reported in the Observer last week Harrow Primary Care Trust (PCT) sent letters personally addressed to children between the ages of seven and 18 years encouraging them to go to a chlamydia screening.
The letters, which were meant to be sent to people between 18 and 24 years, offered the young people the chance to win an iPod if they agreed to be tested. The 'partners' of the children were also encouraged to come along.
Barbara Moran, of Chesnut Drive, received a letter addressed to her eight-year-old daughter. She said: "I know it is a mistake, but it is not nice.
"I don't even let my daughter watch Eastenders, so I don't know what I would have done if she had opened it.
"At the school gates a few mothers had received letters and I told them to open them first in case they had the same and they did - four of us from the same school had them.
"When I rang for an explanation I kept on getting passed around, I got really angry."
The Observer has been inundated with calls from angry parents following the health trust's botched letters.
Koli Pickersgill, of Coledale Avenue, Stanmore, grabbed the envelope containing the letter before her nine-year-old daughter had a chance to open it.
She said: "When you have got children of this age they get so excited to get letters so you leave letters for them.
"One parent's child opened it and only realised something was wrong when her child started having trouble pronouncing the words and grabbed it from her."
Harrow PCT tried to reassure parents no confidential data had been lost and is writing to each family involved to apologise.
Director of Public Health Dr Andrew Howe said: "I would like to sincerely apologise to the families affected by this mistake, and assure them that, of course, chlamydia screening is only necessary for sexually active adults and young people, in line with the national programme to offer chlamydia screening to those aged 15 to 24.
"The trust takes this matter very seriously. An investigation is underway to find out what went wrong and we will take the necessary steps to ensure the same mistake cannot be made again."
Any parents with concerns can contact the trust on 020 8422 6644.