LONDON, (Reuters) – A Briton who strangled his wife  during a nightmare because he believed he was attacking an  intruder, walked free from court yesterday after prosecutors  withdrew their case against him.

Brian Thomas, 59, of Neath in South Wales, killed his wife  Christine, 57, while they were on holiday in July last year.

Prosecutors had accepted that Thomas had a sleep disorder  and so had no control over his body when he attacked his wife of  40 years while they were both asleep.

“I must emphasise that the circumstances of this case are  almost unique in the UK and there have been fewer than 50  instances recorded worldwide,” said Iwan Jenkins, Chief Crown  Prosecutor for Dyfed Powys.

Thomas admitted being responsible but instead of charging  him with murder or manslaughter, prosecutors had sought a  special verdict of not guilty by reason of insanity, the Press  Association reported.

“The consequences of such a finding would have meant Mr  Thomas’s detention in a psychiatric hospital, but it is now  clear that the psychiatrists feel that that would serve no  useful purpose,” Jenkins said.

Swansea Crown Court heard Thomas regularly took  anti-depressant drugs which made him impotent, and he had  stopped doing so before the holiday as the couple, who slept in  separate bedrooms at home, wanted to be “intimate”.

Medical experts said the sudden withdrawal of the drugs  could have led to him having very vivid dreams.