Can a retail outlet refuse to call an ambulance.?

today whilst walking home from work, I walked past a car accident (nothing too serious, but the girl involved needed medical attention, she may have broken her nose) I was asked to call for an ambulance, (typically I had forgotten my phone this morning) but I went to ask the nearest open shop if they could ring an ambulance.

The nearest shop was a small chicken shop (the kind that serves cheap fried chicken), I explained what had happened and if they could call for an ambulance and they said they couldn't.... I walked out quite surprised, and asked the next nearest shop (a charity shop) who called an ambulance. i think the girl was alright, probably quite shocked, it didn't appear to be her fault, someone probably just overtook her at the roundabout, some drivers can be madmen =/.

anyway, I'm just very interested, can a shop legally refuse to call an ambulence, what if their had been a more serious accident later at night when all the other shops where closed, would they still have refused, I'm a bit disgusted. I would understand If I had asked for a plaster or something, because they could get into serious trouble if someone got infected, but surely no one can get in trouble for calling an ambulance.