Armed robbers wielding a seven-inch knife were forced to flee empty handed from a city centre store after screams from a passerby scuppered the raid.
The attackers targeted Premier Stores in Union Street in the early hours of yesterday morning.
One pulled the weapon on the shopkeeper and ordered him to empty the till, while the other stood guard at the front door.
The stand-off, which happened shortly before 3am, only ended when a shocked woman saw the knife and screamed, prompting the pair to make a run for it.
Nobody was hurt during the drama, and the robbers failed to take anything.
Last night Semeine Ali, the owner of the shop, said the young man in his 20s who was working at the time will be supported by colleagues.
She said: “They first came at around 2.30am to observe the shop. They then came back after about 15 or 20 minutes.
“Two robbers came in and showed the knife to my employee who was working there. They started threatening him. First they said they wanted £100, then they said to empty the till.
“The woman saw what was happening and screamed and shouted. She got scared when she saw the knife.
“Our colleague is fine now. He did try to run after them but they went away. This is the first time anything like that has happened at the shop. It is scary but thankfully nobody was hurt this time.”
The employee was due to return to work last night.
Police have issued a description of the knifeman, who is described as wearing a black waist length jacket which had its hood up, a brown scarf, blue/grey jeans and blue trainers.
Detective Inspector Allen Shaw, who is leading the investigation, said: “I would like to stress that no one was hurt during this incident and nothing taken, however the shop worker involved was obviously shaken by what happened.
“A number of people who were in the area at the time have assisted with our inquiries so far and we are following positive lines of inquiry, however I would urge anyone else with information to please get in touch.
“You can contact police on 101 or Crimestoppers on 0800 555111 if you would prefer to remain anonymous.”