British teacher Natasha Hall, who lives in the Bahamian capital Nassau, is worried about her home being waterlogged

The Foreign Office said no specific travel advice had been issued for Britons heading to the region but that people should observe local warnings.

Tourists are being advised to check with their travel agents or airlines to find out if their holidays have been cancelled.

Two British Airways jumbo jets - both fully booked - which had been due to leave Heathrow and Gatwick airports for Miami at lunchtime on Tuesday were grounded.

Safety first

BA is asking others planning to fly with them to call even before they leave home.

"We are sorry for the inconvenience caused by the cancelled flights, but safety must come first," said a spokesman.

Thomson Holidays has not yet decided whether to cancel three Orlando-bound flights leaving from British airports on Thursday.

"Our holidaymakers in the Orlando area have all been given letters advising them of the hurricane threat and giving them contact numbers of all our people out there," said a spokeswoman.

"In addition, our reps have been touring hotels telling clients what is happening."

First Choice, which also has flights due to leave on Thursday, said it was closely monitoring the situation.

A spokeswoman for the UK branch of Visit Florida, the state's tourist office, said: "The Florida coast is bound to get very high winds and UK tourists in the Orlando area inland are being kept informed.

Catastrophe warning

"This is a bad hurricane, but Florida has great experience of handling these kind of emergencies. Everyone will be looked after. Shelters are available. No-one will be abandoned."

The hurricane is currently a category four storm on the Saffir Simpson scale - with winds of 155 mph (250 km/h) but could be upgraded to a five.

The storm crossed the Bahamas on Monday night and headed for Florida at a speed of 15mph.

Todd Kimberlain, a forecaster at the US National Hurricane Centre, said: "Floyd is capable of almost catastrophic destruction."

Such dire warnings struck terror into the hearts of Britons like 19-year-old Sonya Trusty, whose mother is on holiday in Orlando, Florida.

'This is all I need'

Miss Trusty, from Colchester, Essex, told BBC News Online she was terribly worried about her mother, Sheila, who flew to Florida on Friday with her boyfriend, Terry Fosker.

"I'm moving house on Tuesday and it's the last thing I need. I got a phonecall saying there was a hurricane. Why is this happening?" she said.

Miss Trusty said: "My mum phoned me on Saturday to say she had got there alright. She said the weather was 90 degrees and gorgeous and they were having a brilliant time.

"But now they are telling people not to fly and I don't know what hotel they're staying in. I don't know if they're safe."

Miss Trusty, whose sister is on holiday in earthquake-hit Turkey, said: "My mum has been to Florida six times - I've been there twice - and I'm just hoping she's staying at a little place beside Interstate 192 where she's stayed before because there's a big fire station nearby which has an underground shelter."

Disney contingency plans

Hurricane warnings are in force along large stretches of the southern Florida coast.

Officials at Walt Disney World, near Orlando, are studying contingency plans to close the four theme parks and seven resort hotels at the world's most popular tourist destination if inland storm conditions become too threatening.

Florida's Governor Jeb Bush gestures as storm-watchers watch on the hurricane

State governor Jeb Bush signed a declaration of emergency in anticipation of possible major damage.

The most devastating storm in Florida's recent storm, Hurricane Andrew in 1992, had category four status. It killed 26 people and causing an estimated £15bn worth of damage.