To my mind, at least, the central irony that creates the conflict that runs through the whole story is introduced to us in the first paragraph when we meet Paul's mother. Note how the text presents her:
She had bonny children, yet she felt they had been thrust upon her, and she could not love them... Everybody else said of her: "She is such a good mother. She adores her children." Only she herself, and her children themselves, knew it was not so. They read it in each other's eyes.
The irony of this passage is that the mother appears to love her children, and gives every visible proof of her affections through her actions, but this cannot prevent the reality of her heart "turning hard" whenever she is with them. It is this lack of love that drives Paul to go to such supernatural lengths to gain money to make his mother happy, and therefore gain her genuine affection. Note how this irony is referred to again at the end of the story by Uncle Oscar, her brother:
"My God, Hester, you're eight-odd thousand to the good, and a poor devil of a son to the bad. But, poor devil, poor devil, he's best gone out of a life where he rides his rocking horse to find a winner."
Note the criticism that is implicit in this remark. Paul is "best gone" from a life where he is forced to go to such lengths to make his mother notice him. Although Hester has what she wanted, she has only gained it through losing her son.
- In “The Rocking Horse Winner,” the theme of the story is that greed and materialism can never be satisfied and destroy true happiness and peace. Throughout the entire story, the mother wants more and more money; the more she gets, the more she needs. As per her teachings, Paul equates love with luck and money; he strives throughout the story, and essentially sacrifices his life, to get money. Despite trying to stop the whispers, “there must be more money,” Paul himself becomes greedier and almost addicted to gambling and bidding on the horses. It only wears him down and kills him in the end. Greed demands everything and gives only misery in return. It appears than trying to satisfy the mother's hunger for money only gives makes her thirstier for it - she is consumed by her desire for more money, and however much she has it is never enough. The words of her brother at the end of the story, “he’s best gone out of a life where he rides his rocking horse to find a winner,” clearly state the dangers of this materialism while he also implies Paul’s release form his agony. The mother has gained a big sum of money but has lost her son in the process. Thus she clearly shows the dangers and consequences of unbridled greed.