The relationship between Gertrude Morel and her son, Paul, is something that is shown to be incredibly close and, in some ways, a bit too intense. Gertrude Morel, having fallen out of love with her working-class husband, clearly places her hopes on Paul and comes to love him with such an intensity that it makes it difficult for him to form relationships with other women. Gertrude is a character who came from the middle-classes, but married beneath her to Walter Morel, a member of the working class. This is something that she bitterly regrets, and she desperately hopes that Paul can make a future for himself that will allow him to escape a hopeless future of a working class miner. Note how she thinks of Paul in the following quote, taken from Part I, Chapter 4:
All day long, as she cleaned the house, she thought of him. He was in London: he would do well. Almost, he was like her knight who wore her favour in the battle.
The comparison to a knight wearing her favour is particularly apt. It perfectly captures the way in which she pins all of her hopes on her sons, and then on Paul alone. This quote also indicates the obsessive nature of her love and care as she thinks of nothing else except her son "all day long." Her commitment to and love of her son is so strong that she has to be helped to die by Paul, as he gives her an overdose of morphine to finally let her embrace death.