Children as young as nine were sent sexual health check up letters because of an administrative error.

Harrow Primary Care Trust (PCT) has apologised for sending personally addressed envelopes to primary school age children containing advice on the dangers of chlamydia and offering a free screening.

The letters, which have left parents disgusted, also contained the wrong telephone number, directing parents to the Greenwich PCT chlamydia screening hotline.

Charles Whitney, a spokesman for organisation, said: “The intention was to send these letters to all young people aged 18 to 24 years.

“Unfortunately, due to an administrative error, a large number of letters were sent to children and young people of a younger age.”

He said the PCT will be writing to all families who received letters to apologise directly.

Angry parents have been calling and emailing the Harrow Times news desk to complain about the incident.