A spell of fog exposes lack of resilience in Britain's aviation infrastructure yet again

BA has cancelled 30 flights to and from Heathrow so far today (PA)

Airline travellers face another day of disruption, with flights to Heathrow already cancelled because of Wednesday’s weather delays. British Airways’ last wave of short-haul flights was affected by continuing fog at Heathrow. As a result, the first departures to BA’s hub from Belfast, Manchester, Newcastle and other airports have been axed.

Heathrow was worst affected. Two hundred flights to and from Europe's busiest airport were cancelled, and hundreds more delayed, after morning fog disrupted the busy morning schedule.

British Airways cancelled more than 100 flights to and from Heathrow, almost all of them European and domestic. Departures on Aer Lingus, Air France, KLM, Lufthansa. SAS and Swiss were also cancelled. A TAP Portugal departure to Lisbon was seven hours behind schedule.

To try to clear some of the backlog, the airport's hours of operation were extended. A number of incoming aircraft were expected to touch down at Heathrow in the early hours of Thursday morning, including a BA flight from Lyon that was over six hours late.

John Cotton, public affairs director of Birmingham airport, said: "It all goes to show that one shouldn't put all of one's eggs in one basket." The West Midlands, which is campaigning for a bigger role in UK aviation, handled a number of diversions from Heathrow.

Many other airports were affected. Thousands of airline passengers booked to fly to or from London City were grounded, with almost all of the day's schedule at the Docklands airport wrecked by fog.

The two daily transatlantic arrivals - BA's business-class-only jets from New York - were both diverted to Gatwick.

Some flights to Leeds/Bradford were diverted to Liverpool and Manchester, while several departures from the Yorkshire airport were cancelled.

After the weekend disarray due to an air-traffic control failure, and two days of widespread weather disruption, airline bosses are becoming increasingly angry about their responsibilities under EU legislation. While no cash compensation is due to travellers, the airlines have a duty of care - which, today alone, is likely to cost them more than £1m.