I would highly recommend Daniel Yergin's "The Prize" if you want to know more about this and other nationalization attempts.
IIRC, it was the British who discovered and worked to extract the oil before oil became such a force in industrialization. When this first happened, oil wasn't that valuable and I believe the usual term was a flat fee per barrel extracted. The agreement was reach before Iran had any form of democratic government. As oil became more valuable in the period before, during, and after WWII, most governments who signed these deals renegotiated these deals once they realized how valuable the oil is. I believe they wanted to be paid based on market price per barrel.
"Legal basis" is a funny term to use when you're dealing with national governments. In truth, there is very little legal foundation for resolving these dispute until recently and even now it's pretty shaky. I mean, who's legal system do you use? It would seem since all this is happening in Iran, it should be Iranian laws. If that's the case, then the nationalization attempt was legal.
What actually happens, however, is that national governments get involved and other forms of leverage is used. I once talked to a lawyer for a major oil company involved with a dispute with Venezuela. The State Department was involved to some extend but at the end of the day, their leverage was their ability to extract the oil. So "legal basis" is usually not something involved in these sorts of disputes because usually the country with the oil has the upper hand in that case.
Isn't it true though, that in the case of Venezuela, international assets became an excellent leverage point?
For example, Exxon getting court orders to try to have $12 billion in Venezuelan assets frozen in 2008. If I recall, Exxon in its case only received 10% of what it asked for in compensation though.
IIRC, it was the British who discovered and worked to extract the oil before oil became such a force in industrialization. When this first happened, oil wasn't that valuable and I believe the usual term was a flat fee per barrel extracted. The agreement was reach before Iran had any form of democratic government. As oil became more valuable in the period before, during, and after WWII, most governments who signed these deals renegotiated these deals once they realized how valuable the oil is. I believe they wanted to be paid based on market price per barrel.
"Legal basis" is a funny term to use when you're dealing with national governments. In truth, there is very little legal foundation for resolving these dispute until recently and even now it's pretty shaky. I mean, who's legal system do you use? It would seem since all this is happening in Iran, it should be Iranian laws. If that's the case, then the nationalization attempt was legal.
What actually happens, however, is that national governments get involved and other forms of leverage is used. I once talked to a lawyer for a major oil company involved with a dispute with Venezuela. The State Department was involved to some extend but at the end of the day, their leverage was their ability to extract the oil. So "legal basis" is usually not something involved in these sorts of disputes because usually the country with the oil has the upper hand in that case.