"If you join the game you must play according to the local rules", as the adage goes.
In Bank Mellat v Her Majesty’s Treasury  EWCA Civ 449, the Court of Appeal had to consider the right balance between the need to fairly dispose of English proceedings brought by Bank Mellat (the "Bank"), and the risk to the Bank of prosecution in Iran if it complied with the English Court's order for unredacted disclosure.
The Court of Appeal upheld the decision of the first instance judge that, notwithstanding the attendant risk of criminal prosecution in Iran, certain unredacted documents be produced to a confidentiality club. The Court of Appeal ruled that the unredacted customer identities to be disclosed were highly relevant to the Bank's claim for very substantial damages, based on an alleged loss of custom as a result of international sanctions.
In a decision underlining the potential for conflict between the laws of different jurisdictions, the Court of Appeal held that the ability of the English Courts to conduct proceedings in accordance with their own law and procedure should not be overridden by foreign law, even when compliance with the English Court rules entailed an actual risk to a party of prosecution abroad as a result.