Taking a walk on the morning of February 19th, 1949, a man discovered the naked body of 15-year-old Doreen Messenger. She lay in a copse on Haldon Moor, near Exeter, and she had been strangled.

She lived in nearby Heavitree, and her parents had reported her missing at 3 o’clock that morning. The police had no suspect, and her killer might never have been linked with her murder if a convict had not escaped from Dartmoor Prison the next day. Roadblocks were set up, and when a motorist drove through one of them without stopping the police thought he was the convict.

A constable mounted his motorcycle and set off in pursuit. The motorist accelerated. Then his car failed to take a bend, struck a wall and came to a halt. The car wasn’t stolen and the driver was not the escaped convict, so why had he sped through the roadblock? He wouldn’t say, but the police soon discovered the answer.

On searching his car they found a piece of material torn from Doreen’s dress. The man was Sidney Archibald Frederick Chamberlain, a 31-year-old lorry driver who lived with his wife in Heavitree. He’d been having a secret affair with Doreen Messenger, and on February 21st he was charged with her murder.

When he appeared at Devon Assizes, the court heard that he had a mental age of 11. But he knew right from wrong, the prosecution insisted, suggesting that he killed Doreen because she resisted his advances. Chamberlain had told the police that when he took Doreen to their favourite haunt she wept, saying she did not want to go home that night and would rather die.

So had the man with the mind of a child simply fulfilled her wish? His counsel sought a verdict of guilty but insane, but the jury found Sidney Chamberlain plain guilty. Sentenced to death, he was hanged at Winchester Prison on July 28th, 1949.