Rudy Giuliani lost his longtime status as the Republican presidential front-runner yesterday, only hours after being taken to hospital with flu-like symptoms, marking the worst 24 hours of his campaign.

Mr Giuliani turned back his campaign flight from Missouri to New York after becoming unwell on Wednesday evening and spent the night in a hospital in St Louis. He was discharged from hospital yesterday “after doctors found nothing of concern at this time”, a spokeswoman said. Mr Giuliani said that he felt fine.

Candidates fear ill health, or a freak accident, because they can serve as a metaphor for an ailing campaign, or even throw it off track. Richard Nixon injured his knee on a car door during his losing campaign against John F. Kennedy in 1960. It became infected and he had to stop campaigning for two weeks, losing valuable time.

After holding a 13-point lead over his nearest rival last month, The Wall Street Journal/NBC News survey has Mr Giuliani tied with Mitt Romney at 20 per cent, slightly ahead of Mike Huckabee on 17 per cent. John McCain was at 14 per cent. The poll highlights that, with only 14 days until the Iowa caucuses on January 3, no Republican can claim to hold the advantage in a highly unpredictable race.

Mr Giuliani is accelerating his high-risk strategy of devoting his attention to the later contests. He is banking all on a victory in Florida on January 29, which he hopes will propel him on to big wins on “Tsunami Tuesday”, when more than 20 states, including valuable New York, California and Missouri, will hold primaries. This is regarded widely as a gamble because it would mean that he would have to wait nearly a month for his first victory.

He has received more bad news, with another poll showing Mr Huckabee gaining fast in Florida.

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