A former mayor accused of trying to smother his dying mother with a pillow has been cleared after a judge ruled his confessions of killing her were inherently unreliable.

David McLean was accused of attempting to murder his 92-year-old mother, Margaret McLean, by covering her face as he told her: “Sorry, Mum.”

McLean, 72, a former mayor of Winchester, allegedly confessed that he had murdered his mother because he could not bear to see her suffering any longer, which the prosecution said had been an act of “pure and simple unadulterated love”.

However, a jury at Winchester crown court was directed by Mrs Justice McGowan to find him not guilty of attempted murder because she deemed his admissions were not reliable.

McLean’s barrister, Sarah Jones KC, had argued he was suffering from an acute stress reaction at the time of the confessions.

She said: “This prosecution should not have been brought. We say that the evidence any crime was committed is absent, or so fundamentally flawed it should be disregarded.

“This prosecution, this entire case, is founded effectively entirely on the words of a grieving son undergoing an acute stress reaction in the aftermath of his beloved mother’s death.”

Although Margaret McLean died at or around the time of the smothering, the prosecution alleged his actions were only attempted murder because her condition was so grave she could have died at any time.

The pillow was seized and examined but no incriminating evidence was found. The prosecution argued his confessions could be reliable and should be left to the jury.

Describing it as a “highly sensitive and serious case”, the judge said: “I’m driven to conclude that this evidence is so inherently unreliable I’m obliged to withdraw this case from the jury.”

At the start of the trial, the judge told the jury that an assisted dying debate was taking place in the House of Commons but instructed them to disregard it, saying it was just a “coincidence”.

In police body-worn camera footage shown in court, McLean was asked by an officer what he had told an emergency services operator.

McLean replied: “I said I had passed my mother into the next world with the black cushion which is somewhere over there. I put it over her face because she was drowning. I couldn’t watch her die.”

Asked whether he had killed his mother, McLean replied: “Yes I did.”