There is a girl and she is wandering a deserted city going into peoples houses and looking for food, she meets up with a boy who is also wandering and they are on their way somewhere (maybe a port) I think its during the war read it 20 maybe 25 years ago
Could it be Fireweed by Jill Paton Walsh? It's been quite a while since I read it, but the time and setting (London, 1940, during the Blitz) and age of the charcters are similar.
