Simon Calder: So this is Christmas

National embarrassment deepened to abject humiliation last night as more than half a million Christmas travellers remained stranded in the UK. Major arterial roads and the Channel Rail Link ground to a standstill, unable to cope with drifting snow, black ice and "refugees" from Heathrow.

Temperatures were expected to drop to -13C last night and snow is expected across much of the country again today, particularly in southern England, Wales, the Midlands and Scotland. There is little prospect of all the marooned reaching their intended destinations in time for Christmas, even if the airports could be run for 24 hours a day.

Dawn heaped disappointment on a further 100,000 passengers who had been booked to fly to or from Heathrow, and even Eurostar, the usual escape valve for travellers to Continental Europe, came to a standstill, turning away existing customers and airport escapees alike.

The short-term grief caused by a gross lack of preparation for the severe conditions will be accompanied by long-term damage to the UK's reputation abroad – and to the economy.

Only one runway at Heathrow operated all day, and even then at less than one-third of the capacity for one of the busiest weeks of the year. While the steady stream of Airbus and Boeing jets appeared to show the situation improving, in reality the backlog was getting worse: with every hour that passed, thousands more saw their travel plans torn up.

Hundreds of thousands of people did not go to work. As the weather deteriorated across Britain, several regions found themselves isolated from the rest of the country. Much of the West Country was snowed in, and Devon was severed. Councils were accused of sitting on tens of thousands of tons of grit instead of treating roads, so that they could not be accused of running out of supplies. The Government is trying to get more salt from South America, India and Australia.

Air travellers to and from Europe were disproportionately affected, because priority was given to long-haul planes. And because of severe snow-related problems on the Eurostar line from London St Pancras to Paris and Brussels, they could not escape by rail. The Channel Tunnel operator cancelled so many trains that it could not cope even with the numbers of customers already booked. Passengers queued outside the terminal for five hours and then were sent away and told to try again today.

But the most damaging scenes, so far as Britain's reputation is concerned, were beamed around the world from the terminals at Heathrow airport – those of the enraged thousands who are squatting in the terminal buildings in increasingly insalubrious conditions, the stranded grooms, sobbing infants and industrious slum-building scavengers who have become the flotsam of the aviation industry. At lunchtime, the Heathrow authorities erected barriers outside Terminals 1 and 3 – their capacity stretched to bursting point by the stranded, many of them foreigners merely in transit.

Travellers who had been stuck at the airport since Friday night were receiving lower priority than people with confirmed bookings for flights that were still scheduled to depart. As each new flight showed up "cancelled" on the boards, hundreds more people were added to the masses seeking an ever-dwindling number of alternative escape routes from Britain.

In a bid to create extra capacity, British Airways invited passengers booked to travel between now and Christmas Eve to cancel or reschedule their trips for a later date.

Heathrow's owner, BAA, says that passengers will continue to experience delays and cancellations "potentially beyond Christmas".

The former Transport Secretary Lord Adonis said BAA had made the UK look like "a Third World country", adding: "It appears to have made totally inadequate preparations for winter snow and ice." The Coalition's Transport Secretary, Philip Hammond, blamed BAA for not being "proactive".

Each of the BA Boeing 747s scattered across various European airports, having diverted en route from Asia, Africa or America, constituted a nightly bill of around £50,000 – on top of the wasted asset value of the grounded planes and the salaries of the crew.

Equally troubling for the airlines was the fact that the hundreds of tickets rendered worthless each time the screen switched to "cancelled" had been sold at absolute peak fares. An average economy seat on a BA or Virgin flight to New York could command up to £1,000 return; Christmas and new year is when airlines maximise their profits, to make up for the losses that characterise the rest of the year.

The long-term effects look grim. As every new picture of the "refugee camp" at Heathrow was broadcast around the globe, the attractiveness of changing planes in London dwindled a little further. The champagne corks may, if only metaphorically, have been popping in Dubai, Abu Dhabi and Doha with the incompetence: these are hubs that would love to grab more of the global aviation business and are unlikely to be troubled by snowbound runways and iced-over planes.

The British have long been stereotyped as the "wrong-kind-of-snow" folk. What is, in normal times, an endearing characteristic is looking like a sad reflection of over-reliance on inadequate infrastructure.

Transport details:

Gritting

Councils have been accused of sitting on salt supplies but they are, according to David Cameron's spokesman, in "a better place" than they were during last year's crisis when the country came close to running out. The Highways Agency holds 260,000 tonnes of salt compared to 227,000 at the same point in 2009. Some councils said they are rationing it to essential roads to prevent it running out.

Rail

Eurostar passengers at London St Pancras formed a queue hundreds of metres long outside the station in the bitter cold. Some were reported to have been waiting more than seven hours, while charity workers helped out by offering cups of tea.

Eurostar blamed the disruption on bad weather on both sides of the Channel, which reduced typical speeds from 185mph to 105mph, doubled journey times and caused 25 per cent of services to be cancelled. The problem was compounded by an influx of travellers who had expected to go by air but turned to rail in the hope of getting out of the country. Similar problems are expected today.

Commuter trains were hit hard by delays and cancellations, with 25 per cent of all services cancelled. Worst affected were London, Wales, the Midlands, Devon, Cornwall and Scotland. But Transport Minister, Philip Hammond, said the network had performed "broadly satisfactorily".

Air

Heathrow was hit with flight cancellations as passengers continued to wait for news amid poor conditions inside terminal buildings. Of the 1,300 flights that should have taken off or landed, only 435 operated. Only one runway was open yesterday, and that status is likely to continue today.

Other airports suffered cancellations. Gatwick ran a reduced service until early evening when snow forced it to suspend outward flights until this morning.

The Transport Secretary, Philip Hammond, relaxed restrictions on night flights in an effort to clear some of the backlog, but said that the weather had created "a very real challenge from which the system will struggle to recover quickly".

Road

AA Insurance said it had received double the normal number of claims for a Monday in December, while RAC breakdown teams were also dealing with twice as many call-outs as usual. Yesterday was expected to be the busiest day of the year.

Police in Devon said driving was almost impossible away from major roads. Traffic on the M5 was reduced to a crawl and sections of some A roads were closed, including the A385, the A38, A39 and A380.