Hillary Clinton on Tuesday pronounced herself a “proud supporter” of Barack Obama as she urged supporters at the Democratic convention to fall in line behind her erstwhile rival to reclaim a nation in peril.

“It is time to take back the country we love, and whether you voted for me, or you voted for Barack, the time is now to unite as a single party with a single vision,” Mrs Clinton declared in a speech that many observers instantly deemed her most powerful of the campaign.