In pondering how to open this post, I've tried to find a way of expressing my view without repeating a story that has become depressing in its familiarity: the sheer disappointment still felt over Labour's failure to live up to the promise of the 1997 general election. As Liberal Democrats, we knew that the Conservative government needed to go; it was corrupt, sleazy, self-obsessed and incompetent. Tony Blair was no liberal, but he promised to learn from the past and avoid the mistakes of his predecessors, Labour and Tory alike. Foreign policy would no longer be a matter of horse-trading amongst self-interested powers, but would be about ethics, human rights and global peace and security. The sleaze of the Major era would be replaced by a new spirit of openness embodied by the Freedom of Information Act. And liberties at home would be secured by the Human Rights Act.

On this, and far too many other issues, Labour have betrayed their own values and the values of the people who elected and supported them. Even their own early successes such as the Freedom of Information act are at risk of being watered down, and John Reid has spent most of his tenure as Home Secretary trying to undo the work of the Human Rights Act. The Iraq war was prosecuted under a lie which demonstrated abject contempt for the British people and, to this day, Tony Blair refuses to admit that this was wrong.

But if the descent of Labour needed any further demonstration, the Al Yamamah case provides it. In this case, the government called off an investigation by the Serious Fraud Office into alleged bribes paid by BAe to the Saudi Arabian government. These allegations, if confirmed, would indicate a serious breach of both British law and various international treaties. Moreover, they would indicate a level of corruption at the heart of the British defence establishment, in connection with an undemocratic Middle-Eastern government; the very kinds of dodgy arms deals that Labour's 'ethical foreign policy and 'whiter-than-white' stance was supposed to combat.

Worst of all, the decision displays contempt for the law. The government should not have the power to shut down police investigations because they become politically embarrassing; if bribes have been paid then the SFO should uncover this and bring whatever evidence they have to court. This is how justice in Britain is supposed to work - in the interests of truth, honesty and fairness, not secrecy, deceit and corruption.

I don't mind admitting that I cheered when Labour came to power in 1997. But the breath of fresh air has given way to the stale smell of corruption, deceit and sleaze. We can have no trust in a government that behaves in this manner, and their betrayal of progressive values must rank as the greatest disappointment in recent political history.