Obama: I'm off to see my sick grandmother

The Democratic nominee will stop campaigning on Thursday for two days and fly to Hawaii to visit his maternal grandmother who raised him in a Honolulu apartment and "taught him his values". Madelyn Dunham, who will be 86 on Sunday, fell ill several months ago but has deteriorated to an extent where it is "extremely serious", Mr Obama's spokesman said.

The Illinois senator speaks regularly of her "quiet but firm" influence on his beliefs, and after winning his party's nomination in August he said: "She's the one who put off buying a new car or dress for herself so I could have a better life.

"When I hear a woman talk about the difficulties of starting her own business, I think about my grandmother, who worked her way up from the secretarial pool despite years of being passed over because she was a woman."

Mr Obama, whose lead in the presidential race was confirmed by another poll for Reuters which put him on 50 per cent and Republican John McCain on 42 per cent, will resume campaigning on Saturday.

The decision to take a break with a fortnight to go before the 4November election is risky, as some polls show the gap between the two candidates closing.

But experts said it will also have a positive effect as it shows he is prepared to put his family ahead of his political career.