Politicians and police should fear a jail term if they lie to watchdog bodies such as the ICAC and the PIC, a magistrate says.

Politicians and police must fear being sent to jail for lying to watchdogs, a magistrate said during the sentencing of an ex-cop with “memory failure”.

Disgraced former Detective Inspector Shane Diehm, 49, began crying in court as Magistrate Ellen Skinner sentenced him to a maximum of 12 months for four counts of lying to the Police Integrity Commission (PIC).

In handing down her decision, Ms Skinner said his case highlighted the need for general deterrence as the only thing that would “scare” politicians and police officers away from lying to commissions was the threat of jail.

Harm was done to the community when people fronted bodies such as the Independent Commission Against Corruption (ICAC) and the PIC and were dishonest, she said.

“The only promise that is required for them (at the PIC or ICAC) is that they tell the truth,” she said at the Downing Centre Local Court.

Diehm isn’t the only high-ranking public official to face the consequences after shying away from the truth when fronting watchdogs in recent times.

The most recent probe into political donations by the ICAC has had catastrophic career consequences for former NSW MP Tim Owen.

He quit parliament last week after admitting to lying to the corruption watchdog over allegations of shady dealings with developers.

In 2012, former Labor MP Karyn Paluzzano was sentenced to at least one year of home detention for falsely claiming parliamentary sitting-day relief payments between 2006 and 2007 entitlements and then lying to the ICAC about the rorts.

In sentencing her, Deputy Chief Magistrate Jane Culver said Paluzzano “compounded her criminality” by lying to the ICAC.

In 2013 the District Court overturned the sentence on appeal and handed Paluzzano a 14-month suspended sentence.

By Diehm lying to the PIC, Ms Skinner said he showed contempt for the justice system and there was an “element of hypocrisy” regarding his police career.

Diehm was hauled before the PIC in October 2011 to answer questions about a drug-fuelled boys’ weekend on Queensland’s Gold Coast the year before in which former and serving officers were secretly recorded consuming what appeared to be hash cookies and ecstasy.

He admitted to lying to the commission when he initially denied consuming drugs but said he was being truthful when he claimed he “didn’t remember” seeing other cops use drugs.

Ms Skinner rejected this, saying there was no medical evidence to explain his claimed selective memory failure.

“…the community expects that when people promise to tell the truth and lie … there will be consequences.

“There is no penalty other than imprisonment that is appropriate,” she said.

After the decision was handed down, Diehm was granted a stay on the sentence pending an appeal.