Lancashire police have apologised after an officer was filmed threatening to “make something up” in order to lock up a young man.

After the incident in Accrington, the man reportedly complained that the officer had not respected physical distancing guidelines when he approached him and loudly demanded he surrender his car keys on Friday afternoon.

“You’re harassing me … I’ve done nothing wrong,” the man was filmed saying, to which the officer replies: “Do you want me to show you the definition of harassment? Give us your details and then we’ll let you go. Give me the keys. Give me the keys and sit in the car and shut up.”

The man gives him the keys, and then takes a step to the side, prompting the officer to warn: “If you want to fucking step to me and puff your chest out or something like that, then fine, I’ll lock you up. We’ll do that, shall we?”

The man says again that he has done nothing wrong, and the officer threatens to fabricate evidence. “We’ll make something up, public order, squaring up to a police officer. Shall I do that? Who are they going to believe, me or you?”

ITV Granada Reports (@GranadaReports) Lancashire Police issue apology after officer filmed apparently threatening to fabricate offence (see video): https://t.co/VsR1lmZvU4 pic.twitter.com/OSLwV6i125

The man gestures towards his friend who is filming the incident, and the officer says: “You can film all you want.” Another officer then tells the man: “Show some respect.” The outcome of the incident was unclear.

Police said the officers were on the way to search an address under a warrant when they stopped to speak to the group of men, who had apparently just bought a quad bike.

The Lancashire Telegraph quoted the man as claiming on social media: “He started to hail abuse at me, threatening me and saying he will make something up to lock me away. His words were, ‘who they going to believe, me or you?’, while not keeping his two-metre distance, spitting at me while he was shouting.”

The chief constable of Lancashire police, Andy Rhodes, said the officer had behaved in an unacceptable fashion and recognised that threatening to make offences up damaged public confidence in the police.

“The footage shows language and behaviour from one officer which were completely unacceptable and for this I apologise without reservation,” he said.

“We recognise the impact that this behaviour will have had, both on the young man concerned, and on the hard-earned trust and confidence of the wider public, particularly the comments about making offences up. It only takes one incident like this to undo the hard work of so many.”

Rhodes said the man had received a personal apology and that the incident had been referred to the force’s professional standards department for investigation.