We were discussing the UK-US extradition treaty, and how it's unfair because it's not reciprocal. Then the question came up of the standard of proof that's required to extradite someone from the UK to the US. I claimed it was very low, but had no evidence to back it up. The evidence I will now brandish is from an article in the Guardian, where it says that to extradite a UK citizen to face trial in the US:

no prima facie evidence has to be produced

Turning to Wikipedia for more detail on prima facie:

Most legal proceedings require a prima facie case to exist, following which proceedings may then commence

The whole thing is an unjust mess. The Liberal Democrats and the Conservatives made much of its unfairness while in opposition. Now you're in power, sort it out!