A man has been sentenced to four months in prison after being found guilty of attacking the Danish prime minister. The 39-year-old Polish man – who Danish authorities ruled could not be named by the media – punched Mette Frederiksen in the right arm, causing the prime minister to lose her balance, while she was in Copenhagen during campaigning for the EU elections. The Social Democrat leader suffered whiplash and was taken to hospital for a checkup after the incident just before 6pm on 7 June. Afterwards, she cancelled several events and said the attack had given her “a big scare”. In a ruling by the Copenhagen city court, the assailant was convicted of violence against an official while in office. The defendant, who pleaded not guilty, accepted the jury’s unanimous verdict, according to the broadcaster DR. He was also found guilty of several unrelated charges including embezzlement and mortgage fraud. The man, who has lived in Denmark for five years, will be deported after serving his sentence. He was also banned from re-entering the country for six years. During the trial, which started on Tuesday, the man said he recognised the prime minister and recalled “standing face to face” with Frederiksen. But he said he did not remember anything else until he was arrested because he was too drunk. One of Frederiksen’s bodyguards said in the trial that the man had said something incomprehensible to the prime minister before passing her and giving her a “hard blow with a clenched hand on the shoulder”. This, he said, caused Frederiksen, 46, to briefly lose balance. The man had appeared to recognise the prime minister before hitting her. A friend of Frederiksen was meeting the prime minister for coffee on Kultorvet, a popular pedestrian square in the centre of the Danish capital, at the time of the attack. She told the court that Frederiksen was “clearly shaken” by the incident. The court said: “We have emphasised the nature and seriousness of the matter, and that the violence against the prime minister was committed in his spare time.” In 2003, two activists were convicted of the same offence after throwing red paint at Anders Fogh Rasmussen, who was prime minister at the time. At Wednesday’s hearing, the prosecutor also cited a 2013 incident in Aarhus, in which a 23-year-old man fired a water pistol at the then prime minister, Helle Thorning Schmidt, and was sentenced to 40 days in prison. “Blows hurt more than water,” the prosecutor Anders Larsson told the court. “Our case is more serious than the Aarhus verdict.” Frederiksen, in the days after the attack, said she was “not quite myself”. She added: “It was a big scare. In that situation, you need some time with your family and those close to you.” The attack on Frederiksen followed several violent incidents against European politicians. In the preceding weeks, Slovakia’s prime minister, Robert Fico, had been shot and seriously injured, and two German politicians had been injured in separate attacks.