I think we�re getting a bit confused here.
Yes, it�s true that the SFO halted their investigation into the dodgy dealing. However, they certainly did not take that decision themselves and, as I understand it, Tony Blair ordered the investigation to be halted. The court ruling today simply emphasises the fact that the law is supposed to be independent of the executive and that no member of the government had the authority to halt the investigation and essentially override the law. It may well be that Mr. Blair was seeking to protect British interests. However, that cannot be done at any cost and the integrity of the British justice system was seriously undermined by the action. Effectively we gave in to Saudi threats when it emerged that the rulers there may have to let the SFO have a look at their bank statements.
The unrelated issue of the deportation of foreign nationals convicted or suspected of terrorism is similar. The Labour government, in its wisdom, saw fit to incorporate the European Convention on Human Rights into UK law in 1998. In the particular recent case to which I imagine you are referring the judges ruled that the Human Rights of terrorist suspect Abu Qatada would be infringed if he were to be deported. That ruling was made in accordance with the 1998 act. So it is not the judges that need accountability, but the politicians who make the laws.
The law did indeed �step in� in both these cases, albeit in different ways. But in both cases the judges interpreted the law and ignored the actions or wishes of the executive.
And that is precisely what makes the UK different from, say, Saudi Arabia.