An interesting email from one Alex Dakers:

In November 2004 Pursuant to Article 213 (2) (ex157(2)) of the treaty establishing the European Community, Peter Benjamin Mandelson; Crown Steward and Bailiff of the manor of Northstead
not being a person compelled to do so, took an engagement in the nature
of an oath intending to bind the said accused to commit an offence
namely treason. He freely gave a solemn oath of fidelity before the
Court of Justice of the European Union  "To perform my duties in
complete independence, in the general interests of the communities; in
carrying out my duties, neither to seek nor to take instruction from
any government or any other body; to refrain from any action
incompatible with my duties."

This being treason and misconduct in a public office in direct
contradiction to the Oaths he swore as a Member of Parliament for
Hartlepool and that, which he swore as a member of Her Majesties Privy
Council.

The full file of the submission to the court is here:
Download mandelson_notice_of_treason.doc

Now, me, I don’t think that this has a hope in hell. EU Commissioners have been Privy Councillors before and even if he were in breach of the law, it will all get hushed up and overlooked.
Having said that, of course I wish Alex all the luck in the world and perhaps it will open up that other interesting little point about UK politics: ex-Commissioners, those recieving pensions of &#163 60,000 a year, like Patten and Kinnock, also pledge to continue to do the EU’s bidding. Which is rather at odds with their membership of the House of Lords for example.