A court interpreter was the subject of a security alert when guards pounced on a butter knife in his packed lunch.

Saulius Cajaukas, a Russian and Lithuanian speaker, has launched a formal complaint over his treatment at Canterbury Magistrates’ Court.

It's understood he was attending the court to provide assistance in a case.

A routine inspection of his bag revealed the knife among his lunch, along with other items of cutlery.

Guards called police, who attended the scene and quickly established the knife was “not an offensive weapon”.

According to a police statement: “Officers gave the man some words of advice before leaving the scene.”

HM Courts & Tribunals Service has confirmed it received a complaint over the incident in December last year.

Spokesman Zoe Campbell said: “We are in the process of responding to a complaint about the way security contractors handled the confiscation of a knife from an individual attending Canterbury Magistrates’ Court.

“It would be inappropriate to comment further while investigations are ongoing.”

Police say officers were called to the court at around 9.30am on Wednesday, December 23.

Spokesman James Walker said: “Officers attended the scene and it was established that the knife was not an offensive weapon but had in fact been brought in, with other items of cutlery, to eat his lunch with.” He added officers determined it was a butter knife.

In November 2014 parts of the city centre were in lockdown as bomb disposal teams inspected a suspicious package delivered to the court.

The item turned out to be a driving licence and supporting documents hand-delivered in an A3 envelope.

Firefighters, police and paramedics were all called and placed on standby as Army bomb disposal experts inspected the package before declaring it safe.

That incident saw the building and surrounding properties evacuated as emergency services threw up a cordon around the area.