The British Foreign Secretary, Robin Cook, is travelling to Washington for talks which are expected to include the prospect of a new western relationship with Iran.
British officials say neither American sanctions nor the European policy of engaging Iran in a critical dialogue has been effective, and the West had to take the opportunity for engagement opened up by the Iranian President, Mohammed Khatami.
The BBC diplomatic correspondent says this represents anattempt by Britain in its role as president of the European Union to forge a new approach acceptable to both the EU and the United States.
From the newsroom of the BBC World Service