A Guardian story by Matt Weaver at http://www.guardian.co.uk

Passengers today faced further travel misery as continued heavy fog forced British Airways to cancel 170 flights at Heathrow and road and rail routes became increasingly crowded.

Fog-bound BA Boeing 737 on the runway at Heathrow

BA was forced to scrap all its domestic flights from the west London airport on a third day of poor visibility.

While passengers at some other UK airports were affected by delays or cancellations, Heathrow bore the brunt of the disruption, with 40,000 passengers facing heavily delayed or cancelled flights today alone.

BA attempted to clear backlogs by using bigger planes on those flights that could leave, while other passengers gave up, taking to the UK’s increasingly busy road and rail networks.

Despite efforts by airport and airline staff to keep passengers fed, warm and fully informed, tempers inevitably began to fray as Christmas Day moved closer.

David Ranan, a London-based academic whose flight to Munich was among those cancelled at Heathrow, said BA staff had little idea what to do with all the stranded passengers.

"They very quickly succumb to making people stand in line - it's a bit like the breadlines of the former Soviet Union," he said.

"I'm now standing in my third line, and I've got a few more to go after this. There has to be a more efficient way. The fog is not in the sky so much as in the minds of the BA directors.”

The poor visibility has forced air traffic controllers to impose delays on the frequency with which planes land – a measure that particularly affects Heathrow, which operates at virtually full capacity, especially during peak times such as Christmas.

The airport can normally handle up to 44 flights taking off or landing each hour, but that number has been cut by around half on the past three days.

BAA, which owns Heathrow, said around a quarter of its 1,300 scheduled flights were cancelled yesterday, with the same number of cancellations expected today.

Heathrow would normally have handled around 190,000 passengers today, but that figure is likely to come down to around 150,000.

Expat Village is edited and published by Iain Williams in Caracas, Venezuela.