By Andy Silvester What does betrayal look like? It’s easy to identify in love, and pretty simple at work, too. One side committed – the other sniffing around elsewhere. It’s harder to judge in politics, where snake-like behaviour is more easily accepted. Such a quiet betrayal has been at play for decades in how the Treasury treats the City. As we report today, financial services continue to contribute well above the average to the Treasury. The tax take last year was more than the entire education budget. Yet action to allow that particular golden-egg-laying-goose to grow further is sorely lac…