if we examine the word “cornerstone” it means, ‘something of great importance that everything else depends on’. It could be described as a fundamental rule.
There is not text in the European Convention of Human Rights regarding legal profession privilege. It is an important value to be balanced under Article 8 + 6 but its not a cornerstone of Human Rights.
Before we look at the limitations found in the European Court of Human Rights, lets look at how Article 8 is a limited right which is not a great starting point for cornerstone argument.
Article 8 (2) limitations such as: Necessary democratic society and…prevention of disorder or a crime…protection of health or morals
In the Campbell v UK (reported in 1993 in the European Human Rights Report p.137)
On the facts it was held there was a breach of Article 8, but as point of law it was explained that in exceptional circumstances that mail could be read. The court stated that:
‘The reading of a prisoner’s mail to and from a lawyer should only be permitted in exceptional circumstances when the authorities had reasonable cause to believe that the privilege was being abused in that the contents of the letter endangered prison security or the safety of others or were otherwise of a criminal nature.’
Thus, Article 8 cannot offer LPP cornerstone status because of its inherent limitations as a right with exemptions.
In the Michaud v France 2012 case, The Strasbourg Court noted the provision to article 8 that interference with correspondence is permitted insofar as in accordance with the law and to prevent money laundering & associated crimes.
Now let’s look at the CJEU (Court of Justice of the European Union)
Article 6 may not have explicit exceptions the same way Article 8 does. Every Notary public London solicitor knows that, to hold its value up the CJEU have explicitly said sometimes LPP has to be argued against, in the context of Money Laundering.
In the Belgian Bars v Council of Ministers  it was asked if the Money laundering directive would lead to a breach of Article 6 of ECHR. The court held that,
“the obligation to report information to the authorities responsible for the prevention of money laundering stipulated in article 6 paragraph 1 from the second directive on money laundering, considering also the provisions of article 3 paragraph 3, do not breach the right to a fair trial as guaranteed by article 6 of ECHR and by article 6 paragraph 2 from the EU Treaty”.
This shows that instead of Article 6 showing LPP is a cornerstone as Article 6 on occasion requires LPP to be balanced against a competing interest. Article 6 can be an argument for overcoming LPP