Barack Obama was undoubtedly trying to be helpful. But the US president’s intervention to secure an invitation for Prince Charles to a D-Day anniversary event in Normandy has been seen in the media as another sign of Gordon Brown’s weakness.

The resignation of Jacqui Smith, the home secretary, has left the prime minister’s team furious yet impotent

“It’s not for us to start making arrangements about royal family members,” a spokesman for the prime minister said, suggesting any complaints should be referred to Nicolas Sarkozy, the French president. But Mr Brown’s allies admit it is proving impossible to shift the media off a “narrative” that his authority is shot and that Labour is heading for electoral oblivion.