Barack Obama, the Democratic Senator from Illinois who has lit up the early days of the long American presidential election campaign, is rarely considered similar to the man he is trying to succeed.

But last night Mr Obama showed that he shared President Bush's habit of the occasional slip of the tongue, when he unwittingly overstated the recent devastation visited by a tornado in Kansas.

The day after Mr Bush managed to stop himself before describing the Queen's trip to America in 1796, Mr Obama told a rapt crowd in Virginia that a tornado in Kansas had killed 10,000 people last Friday. The actual death toll was 12.

“In case you missed it, this week, there was a tragedy in Kansas. Ten thousand people died -- an entire town destroyed,” the Democratic presidential candidate told 500 people at a fundraising event in a sweltering art studio in Richmond, Virginia.

Mr Obama mentioned the storm, which destroyed 80 blocks of the small town of Greensburg, Kansas, as part of an ongoing argument between America's state governors and the White House over the country's preparedness for natural disasters.

Last year, all 50 governors wrote to President Bush demanding the re-equipping of National Guard units sent to fight overseas in Iraq and Afghanistan. The National Guard, as seen during Hurricane Katrina, is often deployed as a first responder in major emergencies but has been depleted by five-and-a-half years of war since late 2001.

“Turns out that the National Guard in Kansas only had 40 per cent of its equipment and they are having to slow down the recovery process in Kansas,” Mr Obama said during his campaign speech, referring to recent comments by the Governor of Kansas, Kathleen Sebelius, who has complained that the National Guard only arrived in Greensburg two days after the tornado struck.

“How could we have been involved in a war that never should have been authorised, that has already cost us half a trillion dollars?” asked Mr Obama as he continued his critique of the Bush Administration's launching of the war in Iraq.

Towards the end of his speech last night, Mr Obama appeared to realise his mistake. His sleeves rolled up and sweating in the heat of the studio, he said: “There are going to be times when I get tired,” he said. “There are going to be times when I get weary. There are going to be times when I make mistakes.”

His campaign spokesman, Bill Burton, said later that Mr Obama meant to say “at least 10” instead of 10,000. The mistake occurred on Mr Obama's third visit to Richmond in eight months. The Senator's gruelling schedule, which is expected to last until at least the middle of next summer, has been devised in an attempt to stay within reach of Hillary Clinton's rival campaign. Senator Clinton currently leads Mr Obama by at least 10 points in most polls and yesterday received the endorsement of Eliot Spitzer, the Governor of New York.

Times Recommends

• The Japanese Prime Minister is doomed: or is he?
• Brighton company 'involved in cyber attack'
• The art of survival: it’s all in the mind