A two-day strike at Heathrow involving security guards, firefighters, engineers and other workers starts at one minute past midnight on Monday 5 August, and continues until 11.59pm on Tuesday.
Already 177 flights have been cancelled – but a big problem is, no-one seems to know which they are.
Our travel correspondent, who has witnessed many episodes of disruption at Heathrow, assesses the likely impact.
These are the key questions, and the best answers at present.
What is the strike about?
Staff directly employed by Heathrow airport and belonging to the Unite union, including security officers, firefighters and engineers, are in dispute with the employer over pay. They say they are not fairly rewarded, and that Heathrow’s chief executive, John Holland-Kaye, earns in two days what some of the lowest paid airport workers earn in a year.
Last-ditch talks are continuing. A spokesperson for Heathrow said on Saturday: “Unite have rejected our revised pay offer today. While we are disappointed, we will continue to seek an agreement at Acas tomorrow.
“Unite is proceeding with its unnecessary strike action on 5 and 6 August and we regret that passengers looking to get away on well-earned family holidays will be impacted.”
Industrial action is also planned for 23 and 24 August, unless an agreement is reached.
What is the possible impact?
When the series of strikes was first called, the union warned: “Summer travel chaos at Heathrow airport is looming large … in a move that could potentially shut down the airport.” Complete closure looks unlikely; the airport promises “contingency plans that will ensure the airport remains open and operating safely.”
But Heathrow is the world’s busiest two-runway airport, and has very little slack in the system. If travellers are delayed at security and arrive at the gate late, then the airline has to choose between keeping the plane on the ground – which will trigger problems later on in the day – or departing without some of the passengers on board, with all the problems that will create.
Or if a reduction in fire cover forces the closure of one of the two runways, the whole Heathrow operation could swiftly start to unravel.
The other variable is how many of around 2,500 staff rostered to work on Monday and Tuesday stay at home. Some airlines are tentative about cancellations on Tuesday, waiting to see what happens on Monday.
Which airlines will be most affected?
British Airways, which has more than half the flights at Heathrow, is far more susceptible than any other carrier, because the vast majority of its business involves flying people to and from Europe’s busiest airport.
If Lufthansa or Air France encounters a long delay at Heathrow, it affects only a small part of the operation. But for BA, any significant disruption, as we’ve seen already this summer with causes such as air-traffic control or weather, can quickly lead to dozens of cancellations. Significant disruption would cost the airline tens of millions of pounds.
Virgin Atlantic, which also stands to lose millions on its lucrative long-haul flights in August, is trying to minimise problems by switching airports – moving some New York, Atlanta and Boston flights from Heathrow to Gatwick.
What mitigations are planned at Heathrow?
The aim is to reduce the scale of the problem by cancelling 177 flights preemptively, affecting around 30,000 people and representing 7 per cent of the total number of arrivals and departures.
Annoyingly for many passengers, the exact flights have not yet been revealed. Airlines will make their own choices. BA says it will notify affected travellers on Sunday.
On a normal day Heathrow has around 1,300 flights carrying 220,000 people.
If as many prospective passengers as possible are prepared to switch dates (or airports), the effects will be dampened. British Airways is allowing short-haul passengers to take flights from Gatwick or London City instead, or change departure dates to any time up to 12 August. But there are precious few spare seats on any flights at this time of year to switch into.
One airline, Flybe, may take the most unusual step of flying aircraft from Heathrow empty, to avoid the risk of delays. Four services to Edinburgh and one to Newquay may be cancelled; the aircraft will fly out normally, and return with a full complement of passengers.
How will the airport experience be different on Monday and Tuesday?
First, you will be expected to get there earlier. Heathrow recommends you turn up at the terminal two hours before departure for short-haul flights and three hours ahead for long-haul trips (as an aside, I am not sure why there should be a difference; everyone has to go through the same queues, and in my experience long-haul passengers have less cabin baggage and therefore tend to be speedier).
Next, flying on British Airways, you’ll be told to check in all but a small shoulder bag or rucksack. BA says there will be no charge for checking in what would, in normal circumstances, be cabin baggage.
Then you’ll discover how badly – or smoothly – things are running.
Wouldn’t it make sense to turn up even earlier?
Individually, yes: arriving at 5am, could see the security search lines at their shortest.
Collectively, no.
As we have seen on previous occasions, if everyone decides to turn up ridiculously early then chaos results. A kind of self-fulfilling prophecy could conceivably bring the airport to a standstill.
What if your flight is cancelled – or you miss it because you’re stuck in the queue?
Normally airlines take no responsibility for planes missed due to long security queues. But I think it will be different this time, with flexibility shown to passengers who are unable to reach the gate in time; they are likely to be re-booked on the next available flight.
Note that this is not a legal obligation, and so a passenger in this position could not expect to be flown on a different airline.
The position if the flight is cancelled is very different. The airline is obliged to get you to your destination as quickly as possible – which could involve flying you from a different London airport on another airline, which they have to pay for.
Will passengers whose flight is cancelled get compensation?
Since the cause of current cancellations and any future disruption is not the airlines’ fault, there is no entitlement to a cash payout under European air passengers’ rights rules.
What are your rights if you miss an onward connection as a result of delays at Heathrow?
If you are travelling on an end-to-end ticket, eg Heathrow-Dubai-Singapore or Heathrow-Chicago–Nashville, but you arrive too late for the onward connection, then you will be protected. If the first flight is cancelled, you could find yourself re-routed to your final destination. But if you’ve bought the onward flight separately, for example a separate booking from Dubai to India, there is no recompense.
What about people who have booked hotels or cruises: will they be able to claim on travel insurance for any losses?
If the hotel or cruise was booked as part of a package in the same transaction, then the travel company has to help you sort out a new flight or give you a full refund.
If, however, you bought the holiday elements separately, then your only hope is travel insurance. That tricky small print will reveal if you are covered for “consequential losses”.
Meanwhile the threat of a pilots’ strike at British Airways is still looming …
Yes, but the two sides are talking next week and I don’t expect announcement of strike action unless and until those talks break down. Anyone flying up to and including 19 August should be fine.
