LONDON (Reuters) – European Central Bank President Christine Lagarde said the rule of law was of paramount importance, when questioned on Wednesday about attempts by Britain to override some Brexit trade rules related to Northern Ireland. “Reneging on a rule of law that has been established by mutual agreement, without any duress, without proper consideration is a very big issue, and one that we should all be concerned about for the future,” Lagarde said at the London School of Economics. Britain’s government has said the proposed domestic legislation on Northern Ireland is necessary to ensure…