Lyric discussion by Firestopper 

Cover art for The Ballad of Lucy Jordan lyrics by Marianne Faithfull

She is suffering depression and as a result she feels she can't cope any more. She dreams of a life she realises she can't have, and climbs onto the roof. The man who offers he his hand is the fireman coming up to rescue her and the long white car waiting beyond the crowd is an ambulance.

Recurring memories of childhood and blocking out the present, i.e. ignoring the telephone is a distinct symptom of depression, along with dreams of better things. Suicide is not mentioned, but it is hinted. Altogether a very cleverly worded song.

@Firestopper I really think you have a good explanation of the lyrics.