A couple who claim their adopted son was so emotionally disturbed that he made their life hell today sued their local authority adoption agency for damages.

The couple accused Essex County Council of negligence in failing to disclose reports indicating that the boy was "uncontrollable and vicious" and that his appalling behaviour would be "beyond the wildest imagination" of inexperienced adopters.

A High Court judge in London heard that, in the words of his adoptive father, the boy went "off the Richter scale" and attacked other children on a bouncy castle at his seventh birthday party.

When the mother became pregnant, he threatened several times to kill the unborn child and attacked her during a Greek island holiday, putting her in hospital for several days.

The boy, aged five at the time of his initial placement with the couple in 1996 and now 12, was later diagnosed as suffering from attention deficit hyperactivity disorder.

Since 1999 he has been under medication in special needs care.

Gavin Millar QC, for the couple - who cannot be named for legal reasons - told Mr Justice Buckley they were seeking damages for: