By Michael Seamark, Ray Massey and Sean Poulter
Menacing: A volcanic ash cloud rises over Iceland yesterday
Hundreds of thousands of passengers stranded after unprecedented lockdown
Chaos set to cost airline industry alone £30million a day
Vast cloud will cover Britain until at least noon... and Iceland volcano still
Insurers accused of invoking 'act of God' clause to dodge compensation payouts
People with breathing conditions urged to stay indoors
Dark and menacing, this is the giant cloud of volcanic ash that continues to paralyse air travel in Britain.
As Britain awoke to a second day of chaos, health officials warned those with conditions such as asthma to stay indoors.
In an awesome demonstration of nature's power, every plane will be grounded until the wind stops blowing debris towards us from a volcano 700 miles away in Iceland.
Already, all non-emergency air travel has been cancelled until 7pm tonight.
Some experts said there could be disruption for six months from the 'invisible menace' which covers northern Europe. The unprecedented lockdown has already caused the greatest chaos to air travel Britain has ever seen
No jet planes can fly except in emergency because the dust causes their engines to fail.
The day of volcanic ash saw:
All UK airports and many across northern Europe closed
Hundreds of thousands of frustrated passengers stranded - and alternative ways home swamped
A row amid claims that insurers may invoke an 'act of God' clause to avoid £20million compensation
A multi-million-pound bill in lost business for British industry.
I see red: One upside of the ash that saw flights cancelled across Britain was a stunning sunset, seen casting a red glow over Heathrow airport
Last night the vast cloud appeared to be growing and threatened to prolong travel paralysis for millions for days to come.
The Met Office said the cloud would cover Britain until midday today at the earliest. Air traffic controllers ruled out any flights until at least 7pm as a precaution and said the situation remained 'under review'.
Stay indoors, frail warned
The Health Protection Agency said the ash will cause itchy eyes, a runny nose, sore throat or dry couth when the particles land.
Those with from bronchitis, emphysema and asthma were advised to stay inside because the ash could seriously inflame their conditions.
The ash, which will drift down from the north of the country, was predicted to appear as a dusty haze and may smell of sulphur, rotten eggs or strongly acidic.
A spokesman for the HPA said: 'Any health effects are likely to be short term.'
Reports from Iceland said the eruption spewing ash into the atmosphere from Eyjafjallokull showed no sign of abating after almost two days of activity.
A spokesman for the Icelandic Met Office said: 'It is likely that the production of ash will continue at a comparable level for some days or weeks. But where it disrupts travel, that depends on the weather. It depends how the wind carries the ash.'
Even if the current eruption subsides within days, it may not be the end of the travel chaos that the volcano can cause.
It last erupted in the 19th century and Bill McGuire, professor at the Aon Benfield UCL Hazard Research Centre, based at University College London, said if the volcano continued erupting for more than 12 months, as it did the last time, periodic disruptions to air traffic could continue.
He added: 'A lot depends on the wind. I would expect this shutdown to last a couple of days. But if the eruption continues - and continues to produce ash - we could see repeated disruption over six months or so.'
Patient: A couple use their suitcase as a makeshift bench as they wait for news of their flight at Newcastle Airport yesterday
Fed up: Young passengers wait for information about flight cancellations in Terminal 5 at Heathrow Airport yesterday. The disruption could continue for days, experts have warned
Even without further groundings, the knock-on effect of the initial disruption will take days to clear with planes, passengers and crew all in the wrong place.
In a blanket move - worse even than in the aftermath of the 9/11 terror atrocity - air traffic controllers were forced to completely close British airspace at midday yesterday as the volcano pumped massive clouds of ash thousands of feet into the air.
The huge dust cloud, unseen from the ground, slowly drifted across northern Europe at the height that jets cruise across the skies.
The volcanic ash contains tiny particles of rock and even glass which, when sucked into an aircraft's jet engine, can potentially cause them to fail.
While skies above the UK remained clear but eerily quiet, runways emptied and planes were grounded, the air lockdown - the first in living memory - meant misery for millions.
More than 500,000 passengers a day fly in and out of the UK on around 5,300 flights and hundreds of thousands of travellers were left stranded abroad as they planned to return from their Easter breaks.
Airports across the UK became deserted as airlines told passengers to stay at home.
The travel chaos spread across mainland Europe, with airspace closed in Norway, Sweden, Finland and Denmark and all northbound flights from France and Spain cancelled. The closing of UK skies led to a rush for seats on Eurostar, bus and train operators and ferries.
Millions face losing their holidays or the prospect of punishing bills as a result of the airport shutdown.
Those who booked flights as part of holidays they organised themselves are being offered a refund of their ticket price, but there is no right to compensation.
Grounded: Flights from all UK airports were cancelled yesterday after a plume of ash-filled smoke made its way across from Iceland
Choking: The smoke is blown across the skies above houses in Iceland yesterday
Airlines were yesterday clinging to a small-print get-out clause in EU law that means they are not liable where cancellation is 'caused by extraordinary circumstances which could not have been avoided'.
Many airlines will allow people to transfer their booking to the next available flight without extra charge. However seats are scarce and this could be days away.
The net result is that people who have lost their flights face being hit with big penalty charges associated with any hotel and car hire bookings that they cannot take up.
In theory, airlines should step in and help people who are stranded overseas because their return flights have been cancelled. This means providing hotel accommodation, meals and telephone calls until a new flight has been arranged.
However, it could be days before their airline finds them a flight home because most seats are fully booked around the Easter holidays.
As passengers scrambled to find other means of leaving the UK, Gordon Brown said the suspension of flights was a temporary decision and would be reviewed 'at all times'.
But he added: 'Safety is the first and predominant consideration, and if any travelling public are inconvenienced I apologise for that, but it is important that everybody's safety comes first.'
Nobody was able to beat the flying ban. Those caught up included the Duchess of Cornwall, who had been due to fly from Aberdeen to London, and LibDem Treasury spokesman Vince Cable, who had to cancel election campaigning in Scotland.
There was one upside, however, with weather experts predicting that the particles in the atmosphere could cause some spectacular sunsets over the coming days.