William Dowling, 69, slipped mercury into his wife Maureen’s tea at least five times, Preston Court heard. She suffered symptoms including forgetfulness, indigestion and headaches but the mercury had no serious adverse effect on her health.

Dowling, of Colne in Lancashire received a 350-day prison sentence, suspended for two years, the Press Association reported. Judge Robert Brown also imposed an 18-month supervision order. Dowling had admitted administering a poisonous substance with intent to injure, aggrieve or annoy.

Prosecutor Mark Lamberty said Maureen Dowling, 64, used to visit her old home regularly and had gone to see her estranged husband in February last year.  He said: “The defendant made her a cup of tea and, as was customary, poured that in a white china beaker with a yellow floral motif. “While she was drinking it, she noticed what appeared to her to be ball bearings at the bottom of the cup. She showed it to her daughter Julie and commented she had noticed that in her cup before, and it always appeared to be the situation that the defendant made the tea. 

“She said there were four or five occasions she had noticed that in the past. She commented and he riposted ‘they must be coming off the kettle’ and in another comment ‘they must be coming off the teabags’.”

Lamberty said when Julie, 43, examined the contents of the cup, which appeared to be liquid metal, “the defendant seized the cup from her, threw the contents into the bin and appeared agitated”.

When Maureen noticed the silvery substance in her tea cup the following week, the defendant told her he really must clean the kettle, Lamberty said. He said the effects on Maureen were “devastating” and had caused her to lose her self confidence and created a family rift. Paul Lewis, for the defence, said in mitigation: “The actions he undertook were only intended to annoy his wife so she would feel the need for him to care for her and so resurrect their relationship. He had no intention to cause her any significant harm. His actions were ill thought-out.”

Judge Brown told Dowling that his wife of 28 years had left him because “she had become fed-up of what she regarded as your controlling attitude towards her.” He said: “In judging the seriousness of the crime you committed, your ... wanting her to return to your care is irrelevant.”