I'd say, from the picture, that it's a small Crab Apple, a bit like 'Red Sentinal' but smaller. Are there 5 chambers for the pips when you cut horizontally rather than one stone?.. This would put it into the Malus/Pyrus section of the rosaceae rather than prunus. There are a lot of different ornamental crabs and they do cross and self seed. People are often mislead into thinking that it's a Cherry by the long stalk to the fruit.
Hope this helps
Richard