Flights at London airports are being disrupted due to heavy fog this morning.
Passengers at Heathrow, Gatwick and London City airports are facing delays, European air traffic controllers said.
London City airport advised passengers to check the status of their flights before travelling to the airport.
Posting on Twitter, a spokesperson said: "We're experiencing some delays this morning as a result of low visibility, check with your airline before you travel."
<blockquote class="twitter-tweet" data-cards="hidden" data-partner="tweetdeck">We're experiencing some delays this morning as a result of low visibility, check with your airline before you travel <a rel="nofollow" target="_blank" href="https://www.awin1.com/awclick.php?mid=9&id=222025&p=http://t.co/iEoxJH7mQq" class="body-link" data-vars-item-name="BL-178846-http://t.co/iEoxJH7mQq" data-vars-event-id="c23">http://t.co/iEoxJH7mQq</a>— London City Airport (@LondonCityAir) <a rel="nofollow" target="_blank" href="https://twitter.com/LondonCityAir/status/511765054057119744" class="body-link" data-vars-item-name="BL-178846-https://twitter.com/LondonCityAir/status/511765054057119744" data-vars-event-id="c23">September 16, 2014</a>
Meanwhile Heathrow said there were no "significant issues" due to fog but also advised customers to check the latest information with their airline.
Despite initial reports, Gatwick airport insisted flights were running as scheduled.
A spokesperson posted on Twitter: "Gatwick Airport is operating well this morning. Please check in as normal for your flight."
The Met Office issued a severe weather warning for the south east of England this morning.
<blockquote class="twitter-tweet" data-partner="tweetdeck">Good morning from Gatwick. Please let us know if we can help you through the airport today.— Gatwick Airport LGW (@Gatwick_Airport) <a rel="nofollow" target="_blank" href="https://twitter.com/Gatwick_Airport/status/511768352860418048" class="body-link" data-vars-item-name="BL-178846-https://twitter.com/Gatwick_Airport/status/511768352860418048" data-vars-event-id="c23">September 16, 2014</a>
It said: "Widespread fog is affecting much of East Anglia, south east England and the East Midlands this morning with visibility reduced to 100 metres or less in places.
"The public should be aware that this will lead to difficult travelling conditions during this morning's busy period. The fog should gradually lift and disperse during the morning."
Thick fog is also causing delays in several other European cities including Lisbon, Amsterdam and Zurich, according to Eurocontrol, the European Organisation for the Safety of Air Navigation.
Additional reporting by PA
