A spokesperson for the West Sussex airport said: “Temporary air traffic restrictions have been put in place due to fog causing poor visibility.

“Some flights may be delayed throughout the day.

“London Gatwick apologises for any inconvenience.

“Passengers should contact their airline for further information.”

Flights at Stansted Airport were affected by the weather conditions on Saturday, while live departure boards showed delays at Heathrow, Luton and Manchester Airports.

Nats, the UK’s main air traffic control provider, said temporary air restrictions will continue on Sunday as airfields are affected by fog.

A Nats spokesman said: “While the weather conditions have improved, fog continues to affect some airports in London today.

“Temporary air traffic restrictions are therefore in place at airfields with low visibility to maintain safety.

“Our teams are working closely with the airports and airlines to minimise disruption but passengers should check the status of their flight with their airline.”

If you are flying from a UK/EU airport or on a British/ European airline and are delayed in arrival by at least three hours, the presumption is that you are owed hundreds of pounds in compensation.

The payment depends on distance:

• Under 1,500km, for example London to Nice: £220 or €250
• 1,500-3,500km, such as Manchester-Malaga: £350 or €400
• Above 3,500km, eg Birmingham-Dubai: £520 or €600. If a long-haul arrival delay is between three and four hours, the compensation is halved.

The only way the airline can avoid paying out is by demonstrating “extraordinary circumstances” were responsible.

extraordinary circumstances refers to “political instability, meteorological conditions incompatible with the operation of the flight concerned, security risks, unexpected flight safety shortcomings and strikes”.

For delays of under two hours you have no rights (unless a short delay in the UK triggers a missed connection and much later arrival at your final ticketed destination – see below).

For longer delays, the airline should provide refreshments as appropriate after a specified length of time. This applies regardless of the cause of the delay.

The time at which the duty of care kicks in depends on the distance you are flying:

• Short flights (up to 1,500km): refreshments after two hours.
• Mid-haul journeys (1,500 to 3,500km): three hours.
• Longer trips: four hours.

Note that if the airline believes providing the care would further delay the flight, it need not deliver.

If the delay extends overnight, the airline is obliged to find and pay for a hotel room. In practice, carriers often say, “too difficult”, and invite the passenger to book their own and reclaim later.

While this practice does not comply fully with the rules, aviation authorities tend to turn a blind eye to it.

On Saturday, 19 flights at Heathrow have been cancelled so far with another 455 delayed, while at Gatwick, 320 are delayed and 16 have been cancelled.

Disruption is continuing at some of the UK’s busiest airports as thick fog blankets the country.

Flights at Stansted airport have been affected by the weather conditions, while live departure boards showed delays at Heathrow, Luton and Manchester airports.

Passengers at Gatwick airport on Saturday morning were warned to expect disruption because of the poor visibility and told to contact their airline for updated information.

Patches of thick fog could reduce visibility to just 100 metres in some areas, the Met Office said.

A spokesperson for the Gatwick said: “Temporary air traffic restrictions have been put in place due to fog causing poor visibility.

“Some flights may be delayed throughout the day.”

Sunday is expected to be the airport’s busiest day during the holiday period, with 769 flights planned.

Nats, the UK’s main air traffic control provider, said temporary air restrictions would remain in place on Saturday in areas with low visibility.

A spokesperson added: “Restrictions of this sort are only ever applied to maintain safety.

“We continue to monitor the situation and have a Met Office expert embedded within our operation to ensure we have the latest available information.”