A "perfectionist" from St Albans who became depressed after making mistakes took his own life after suffering with untreated depression, an inquest was told.

John Keen, 64, was found at his home in Highview Gardens by his partner and neighbours on October 4.

Mr Keen's partner Patricia Stroudley had become concerned for the welfare of Mr Keen after he failed to meet his friend on Friday night, and with the help of neighbours she forced entry into the house and found him dead on the floor.

Hertfordshire Coroner's Court heard Mr Keen had written a note to his partner of 12 years and another to the coroner’s court outlining his intention to take his life.

Mr Keen, who was the eldest of four boys and a retired chartered mechanical engineer, died from asphyxiation, the inquest was told.

Assistant coroner of Hertfordshire Edward Solomons read out a letter from Ms Stroudley, which said: "I knew John from early 2002 and went through three depressive periods with him.

"It seemed to start when he made an error with a task. He was a perfectionist, a very careful man.

"He had been a mechanical engineer working on projects throughout the world and when he gave this up in the mid 1990s, mainly due to stress and anxiety he put all his efforts into doing tasks at home and if these did not go well he let felt he had let himself down.

"In 2000 he had a bad spell of depression after two small errors he made that he felt were inexcusable - a mistake on a tax return and destroying an old Hoover.

"He managed to pull through the depression and after a month or so he was back to being John again and a he said a new challenge often bought him out of a depression."

The court heard Mr Keen’s last depression seemed to stem after a mistake repairing a windowsill at home on September 27.

The court heard on Wednesday night Mr Keen "did not sound good" and when he failed to show on Friday Ms Stroudley knew something was "gravely wrong".

A library receipt found on Mr Keen was dated 11.53am on October 2, and Mr Solomons said Mr Keen died sometime after that.

Mr Solomons said: "He was a man much loved by his family. A perfectionist, who tried to mend things when required."

He concluded Mr Keen took his own life while suffering from untreated depression.

He added: "I can only express, inadequate as it may be, very sincere condolences to the whole family and to you Patricia and to hope you remember him as he hoped to be remembered, in the good times which I have no doubt there were many and particularly when he was not suffering from his depressive illness."