Yes, I was referring to the UK's removal of that protection. Of course I'd feel differently if a relative had been murdered - it's why justice requires impartial arbiters.
The thing is, though, our justice system is supposed to err on the side of the suspect: innocent until proven guilty. "Better to let a dozen guilty men go free than to jail one innocent man": an exaggeration perhaps, but a long-standing core principle and one I support. The accused should face a fair trial - rather than evade it through flight or endless delaying tactics - and if that trial ends in acquittal, that should stand absent truly exceptional circumstances such as jury tampering.
On a related note, then: as noted earlier in this thread, one of McKinnon's grounds for objecting to extradition to the US was the (false) claim that their plea-bargaining is something not allowed here, meaning he would have less procedural protection there than in the UK. How would you feel seeing a UK extradition request denied because the UK now genuinely lacks a procedural safeguard other countries still hold dear?
It has happened in the past that the police have been convinced of someone's guilt ... gone to court ... been angry about losing - then years later, the actual culprit is found. It has sometimes even happened that they convinced a jury and jailed someone - then years later, they find someone else did it, so an innocent man was jailed or worse. Allow the police a second or third bite of the cherry if the jury aren't convinced the first time, you compound the risk of such a miscarriage. For eight centuries, once a court sets you free, that has been the end of it. Also remember it's a principle of justice that the prosecution has to let the defence see all their evidence in order to prepare a proper defence. They go against a suspect with enormous advantages: an entire police force, labs full of specialists, full-time lawyers who do nothing but prosecute cases every day - so, to level the field and stop them grinding a target down in a war of attrition, they have got to 'show their cards', and they get one shot at convincing the jury.
The US sets the bar higher for overturning an acquittal, as I understand it: you can be tried again if you had somehow corrupted the first trial sufficiently to negate it: jury, judge or witness tampering for example. Apart from that sort of scenario, giving the prosecution one chance to make their case makes sure they do a thorough and honest job.
The Lawrence story is an interesting one in this respect. The Crown Prosecution Service concluded there was not enough evidence (at the time) to convict - but the Lawrence family insisted on going ahead anyway. Since there was indeed insufficient evidence, the prosecution failed: the court found them not guilty and set them free. If the victim's family had listened to the prosecution experts, there wouldn't have been any issue: once there was real evidence, they could just have prosecuted properly, once, as it should be. Perhaps the real failing of the system was not that the first prosecution's result bound the prosecution's hands, but that the family were allowed to try to prosecute it themselves and fail?