'What was the point,' he says, 'of all those morning paper rounds and extra car cleaning chores when all I got out of it was three weeks' worth of new bike?' Discourses on the viability of the protestant work ethic now fall on deaf ears. He feels he played the game and lost.
I had been impressed with his single-mindedness in saving for the bike. A 21-gear mountain machine does not come cheap, and when his pleading for it got him nowhere, he presented me with a deal. 'Mum, how about if I pay half towards it - I've seen the one I like, it's expensive but its got front suspension, I've always wanted that. I could get a paper round and save all my pocket money so that you would only have to pay half.'
My argument that he needed neither front suspension nor a surfeit of gears to ride the couple of miles to school or around the local park made no impression on him, so the deal was struck. He would pay half by saving for nine months and I would pay the rest. He had some birthday money and by staying in and not buying any new computer games his money accumulated.
I felt he was taking responsibility for making something happen in his life that was important to him. He knew what he wanted, had planned a strategy to get it and was rewarded by his dream bike. What he had not foreseen was that although the bike was his, his right to keep it had to be constantly defended.
He had invested in a combination lock and always used it, but this particular Saturday afternoon, having been to the cinema with his friends, he returned to the local shopping centre's bike stand to find his front wheel securely attached, but nothing else. We have discussed why he did not attach the chain to the bike's frame rather than its wheel. He says: 'I just didn't think anyone would really nick it, mum. The shopping centre's a busy place, wouldn't someone have noticed it being pinched and stopped it?'
His navety at thinking passers-by would intervene, even if they noticed, made me realise the sense of idealistic optimism many teenagers still have despite their regular diet of violent computer games and easy access to the world's atrocities via the media. Or perhaps I have just become jaded. There was a time in my own youth when I would have automatically stopped to help anyone in trouble or even step in the path of a thief, but as I have grown older I have become more wary. I am almost sure that if I saw a group of youths who looked as if they were dismantling someone's bike, I would feel uncomfortable but I would not intervene for fear of both verbal and physical abuse.
My son, however, feels personally let down by the whole system and is now even questioning the value of studying hard for his GCSEs. 'What's the point of working myself to death now to get things when I'm older?' he argues. 'I'd rather enjoy life while I'm young, not have my head stuck in a pile a books - that will take me precisely nowhere.'
I must admit that the route we had planned for A-levels, then university and a job, looks pretty shaky these days but I am beginning to wish I had bought him the bike outright, so that he would not now be having this crisis of confidence in the legitimacy of our capitalist society. OK, so he worked hard, then bought and lost a dream, but I never told him life was either easy or fair. Perhaps the episode will give him a more philosophical outlook. I am just hoping his natural buoyancy will return before much more of his coursework is due in.