A toddler was left with burns on her hands after grabbing some loose wiring under a shelf at a Northampton Subway outlet.
The girl was with her dad, Matt Wood near the counter of the Subway at Riverside on Saturday when he heard her scream.
He looked down and saw his daughter crying with pain.
He quickly checked to see if she was okay and saw wiring hanging down without any protective casing.
He said: "There was an almighty scream like I'd never heard before.
"Her hands had swollen up and she was crying."
Mr Wood told a member of staff that his daughter had been injured by a loose wire but he says the worker denied there was any such danger.
An argument ensued and police were called to the premises.
Mr Wood said: "It was preposterous. The wiring was there for anyone to see and they were denying it.
"Not once were we offered first aid, not once were we offered an apology. It's beyond a joke."
The girl suffered electrical burns to her hands but after being checked over in hospital, she was deemed to be otherwise unharmed.
A spokeswoman for Subway said the manager insists the wires were not live.
She said: "On behalf of the Subway brand, we are all very concerned to hear about this. We take the safety of our customers and Subway employees very seriously.
"Whilst there was found to be some loose wiring under a counter in the relevant store, we have been informed by the franchise owner that this was not live and that there was minimal risk to customers. This issue has now been resolved.
"Staff responded to the incident and spoke with the father, who was understandably upset. Unfortunately, the situation escalated and the store had to call the police in the interests of restoring calm.
"We are conducting a full internal investigation."