A man who admitted planting a hoax bomb at a polling station on the day of the general election last December has been jailed for three years.

Peter Conoboy placed the device in the foyer of the tower block where he lived in Motherwell, North Lanarkshire, near a community centre that was to be used as a polling station on December 12.

The 48-year-old previously admitted the offence at the High Court in Glasgow in July, when no motive for his actions was made clear.

Appearing again on Tuesday for sentencing via video link, Conoboy was sentenced by judge Lord Matthews to three years in prison with two years and three months still to serve.

The court previously heard bomb disposal experts believed the device – spotted at 12.50am by a resident making a phone call – was viable but after it was disabled through a controlled explosion it was found to be a hoax.

Lord Matthews told Conoboy residents in the ground, first and second floors of Glen Tower had to be evacuated, which he said would have been “irritating” given the time of day.

He also said the incident would have caused emergency services “considerable expense and inconvenience”.

People who were registered to vote at the tower block were told to attend an alternative polling station at Knowetop Primary School in the town.

No how-to guides on explosives were found on Conoboy’s phone or laptop but five videos of terror attacks were discovered, including those on London Bridge and in Christchurch, New Zealand.

William Lavelle, representing Conoboy, told the court on Tuesday his client “couldn’t remember any videos” that had been referenced and added his son used the same computer to listen to rap music.

Mr Lavelle also said he had “no explanation why Mr Conoboy did this” but told the court he had been drinking alcohol that night, which “no doubt played a part”.

Lord Matthews said background reports suggested Conoboy had “problems with mental health … but had not been diagnosed as suffering from any mental illness”.

He added the only conclusion was “this episode was caused or contributed to by gross intoxication”.

Sentencing Conoboy, Lord Matthews told him his “conduct will not be tolerated”.