A father was headbutted in Bakewell in front of his young son after an altercation with a dog walker.
At about 12.50pm on Thursday, the 51-year-old man was walking along North Church Street with his ten-year-old son following a shopping trip.
A man and woman were walking towards them with two dogs, one of which was not on a lead.
The dog ran towards the victim, who accidentally trod on its paw.
He apologised to the couple but the woman verbally abused him before the man headbutted him hard in the face, causing a significant cut to his upper lip which required stitches.
Police said the man was white, in his late 30s or early 40s with greying fair hair and prominent ears.
He was about 6ft tall and wearing a light coloured, short sleeved top and light coloured trousers.
The woman was white, in her 30s with red-brown curly shoulder-length hair. She was wearing a dress.
A Derbyshire police spokesman said: “The incident happened when the town was busy with people visiting Bakewell Show so officers believe there may be witnesses who have yet to come forward.”
Witnesses or anyone with information should call police on 101 or Crimestoppers on 0800 555 111.