A 76-year-old retired builder from Barnet, north London, has admitted to deliberately poisoning his neighbour’s koi carp pond using motor oil and detergent, citing frustration and sleep deprivation caused by the noise of a water pump. Gerry Duffy pleaded guilty on the first day of his trial at Willesden magistrates’ court to three counts of damaging property and one count of unlawfully destroying fish.

The incident took place in March, when Duffy allegedly climbed into the garden of his neighbour, Andreas Ptohides, and damaged the pond's water pipes and electric pump, as captured by CCTV footage. Prosecutor Shahid Iftikhar told the court that the attack killed five or six of Ptohides’s koi carp and caused approximately £565 in damage, including the loss of fish valued at around £125.

The dispute reportedly began as a result of the persistent noise from Ptohides’s pond pump, which Duffy said had severely disrupted his sleep and mental well-being. According to court testimony, Duffy had confronted his neighbour multiple times about the noise, warning that he would take action if it was not addressed. Initially, Ptohides had agreed to stop the pump occasionally but later reversed this, citing concern for the fish’s welfare.

Duffy, who lives in a studio flat adjoining Ptohides’s garden, sought assistance from local authorities when the noise continued. However, an environmental officer’s advice—that he either close his window or move residence—offered no resolution, exacerbating his distress.

Defence counsel Elliott Stern described Duffy as having been "driven completely insane" and acting out of character due to ongoing frustration and sleep loss. Stern noted that Duffy suffered from several health issues, including chronic obstructive pulmonary disease (COPD), skin cancer, anxiety, and depression, and argued that his client was pushed beyond rational thinking at the time of the offences.

Magistrate Matthew Cornish, while recognizing some degree of premeditation given the events occurred over multiple days, issued a two-year conditional discharge and ordered Duffy to pay full compensation of £565 to Ptohides. The magistrate’s decision reflects a balance between acknowledging the criminal damage caused and the mitigating factors linked to Duffy’s mental state and health.