Barack Obama started his day with a friendly boost for his beleaguered British host Gordon Brown, who clearly enjoyed the US president’s genial affirmation of the Anglo-US “special relationship”. He ended it with a cup of tea with Queen Elizabeth, followed by a G20 dinner at Downing Street.

In between, the US leader put serious meat into his promise that he would “hit the ground running” on taking office. In the process, he drew a clear line between his approach to diplomacy and that of George W. Bush – namely, that it can often be worth the effort.