It was announced in the High Court on Monday that Tony Blair will not face prosecution over the role that he played in the 2003 invasion of Iraq.

The possibility of such a case is one that I have spoken about in the past on my YouTube channel but the decision yesterday will act as a significant roadblock.

The case centred around whether there is such a thing as the crime of aggression in English law. On the face of it this may seem like an unusual question as surely we ought to know what is and is not a criminal offence within our own legal system. This particular context, however, is quite unique.

The crime can trace its history back to the Nuremberg Trials after World War II and although the prosecutions at that International Military Tribunal did proceed as planned it has always been difficult to nail down a precise definition.

Nevertheless aggression is regarded as a part of international customary law and this much can be agreed upon even within the context of the English legal system as held in the case of R v. Jones (Margaret) [2006] UKHL 16.

That decision in 2006 had a huge and arguably outsized influence on the decision with respect to Tony Blair on Monday because the judges in the case went on to consider if this element of customary international law had a place in the English legal system.

In broad terms international customary law does by necessity form part of the English legal system but this is not the same as creating a brand new offence. Therefore there are a number of reasons why the House of Lords decided against allowing for a crime of aggression domestically:

• International law should be transposed into English law by way of a statute.
• To do so would create uncertainty in the law.
• It would lead the courts towards making judgments on the government’s decision to go to war in the first place.

This is a good basis for a decision and given the way that the rules of precedent operate it is unsurprising that the High Court came to the decision that it did. The more problematic issue is that the judges blocked the issue from going any further.

The context of the decision in Jones is quite different from what we are considering here and the question is important enough that this should not simply be the end of the line for the claimant, former Iraqi General, Abdul Waheed Al Rabbat.

It may well have been that the Supreme Court would go ahead and affirm the decision in Jones and even have the opportunity to set a precedent for future private war crimes prosecutions. A further discussion of the relationship between domestic and international customary law would also have been useful from the perspective of the top court in the UK.

In the end not only have we been denied this opportunity but Tony Blair has been allowed to evade prosecution on the basis of a decade-old decision in an unrelated case. It is hard to feel that the justice system has fully done its job.