Update: Hampshire prepares for battering from hurricane-force storm - Video

The giant weather front is just hours away from the British Isles and is set to hit the county with winds of up to 80mph and torrential rain.

Warnings have been issued of damage to buildings, commuter chaos and flooding.

The storm forming over the Atlantic is expected to hit the south coast overnight growing in intensity in the early hours of Monday morning and causing chaos ahead of the rush hour.

It also comes as thousands of athletes prepare for tomorrow’s Great South Run in Portsmouth and other events at risk include the Tichfield Carnival.

The Met Office says gale force gusts could bring down trees and cause structural damage, leading to power cuts and transport disruption on Monday morning.

The Environment Agency has warned of flooding across most the region with 25mm of rain expected to fall in just six hours.

Atlantic storms of this type usually develop further west across the ocean, losing strength by the time they reach the UK and Ireland.

But this is expected to appear much closer to land, potentially moving across the country while in its most powerful phase.

Prime MInsiter David Cameron said he has spoken to the organisations responsible for public safety during the storm.

He wrote on Twitter: ''I've just chaired a call with various Government departments and agencies to hear about all the plans to ensure people are protected from tonight's storm.''

The British Red Cross has teams ready to assist people stricken by the storm, and urged households to prepare for possible blackouts.

Simon Lewis, head of emergency response at the humanitarian organisation, said: ''It's important people are ready should the worst happen.

"Make sure you have torches at hand, as well as a battery powered or wind up radio to keep up to date with weather warnings and information for your area.

''Taking a few minutes to get together an emergency kit can make a huge difference.''

Darron Burness, head of the AA's flood rescue team, said: ''If the predicted storm strikes, the timing couldn't really be worse, potentially causing significant travel disruption on Monday morning, which is one of the busiest times on the roads.

''Strong wind and torrential rain is an unpredictable and hazardous combination, which can be quite overwhelming when you're driving.

''There's likely to be tree and other debris on the roads as well potential flooding, so it's very important to keep your speed down and drive with great care, particularly on country roads early on Monday morning when it's still dark.''

A spokesman for South West Trains said: “We are monitoring this situation very closely and will update this message at 13:30 on Sunday 27 October to provide further information about the train service on Monday 28 October.

“The risk of falling trees as well as damage to buildings and equipment is high. These conditions present risks to the railway from localised flooding, fallen trees and debris on the tracks.

“Our maintenance teams are visiting our high-risk sites over the weekend to carry out mitigation work for both flooding and fallen trees. We have also arranged for additional staff to be present across the network at key locations.

“All areas of our network are subject to these conditions with the highest risk areas being on the lines between Weymouth and Basingstoke via Southampton and between Portsmouth and Guildford.”

Steve Willington, chief forecaster at the Met Office said: “''This is a developing situation and we'd advise people to stay up to date with our forecasts and warnings over the weekend, and be prepared to change their plans if necessary.

"We'll continue to work closely with authorities and emergency services to ensure they are aware of the expected conditions.''

It brings back chilling reminders of the Great Storm of October 1987 when 115mph winds battered the country.

Insurance companies have advised households to take steps to protect themselves and their property.

People should also establish evacuation plans, place valuable items upstairs to limit flood damage and ensure gutters are clear so water can drain away.

The storm has been named St Jude after the patron saint of lost causes, whose feast day is tomorrow.

It will develop over the Atlantic and is expected to hit the South West late tonight, before moving north-eastwards across England and southern Wales.

Heavy rain will accompany it, with strong winds in the early hours of tomorrow, but the storm is expected to have moved out over the North Sea by lunchtime, leaving strong breezes in its wake.

The Met Office described the storm as not one "you would see every year", and said the expected wind strengths would be similar to storms in March 2008, January 2007 and October 2000.

It has issued an amber warning, meaning ''be prepared'', for the southern half of England and the southern half of Wales.

It gave a lesser yellow warning, meaning ''be aware'', for the rest of Wales and England up to the border with Scotland.

Frank Saunders, chief forecaster at the Met Office, said last night: "We are confident that a severe storm will affect Britain on Sunday night and Monday.

"We are now looking at refining the details about which areas will see the strongest winds and the heaviest rain."