Hundreds of airline passengers bound for London have been forced to land in Ireland as a result of freezing conditions.
Six transatlantic flights on their way from the US to Heathrow were redirected to Shannon Airport. Some of the planes were in UK airspace or on approach to London when they were ordered back over to Ireland.
Shannon Airport Authority confirmed arrangements are being made for stranded passengers on at least one of the flights to stay overnight.
The affected routes included Heathrow-bound services from Dallas, Miami, Houston, Washington, Denver and Atlanta. The aircraft were a mixture of Boeing 747s and 777s.
Shannon spokesman Eugene Hogan said the flights were redirected from this morning.
A number of Aer Lingus flights to London Heathrow were also grounded by the weather as were two Ryanair services on the Dublin and Birmingham route.
Aer Lingus said flights between Dublin-London Heathrow, Dublin-London Gatwick, Cork-London Heathrow, Shannon London Heathrow and Belfast-London Heathrow had been affected.
The airline said it had "been instructed by the airport authorities to reduce the number of flights we operate" on those routes due to the severe weather.
Ryanair said passengers booked to travel on cancelled flights could transfer to the next available Ryanair service free of charge or apply for a refund.
London's Gatwick Airport said it had received 8 cm of snow overnight but it had remained open, and would be running all scheduled flights. However, many of Britain's other airports were forced to shut runways overnight and warned there could be further disruption today.
Affected Aer Lingus services:
EI 152 Dublin-London Heathrow
EI 153 London Heathrow-Dublin
EI 154 Dublin-London Heathrow
EI 155 London Heathrow-Dublin
EI 168 Dublin-London Heathrow
EI 169 London Heathrow-Dublin
EI 176 Dublin-London Heathrow
EI 177 London Heathrow-Dublin
EI 710 Cork-London Heathrow
EI 711 London Heathrow-Cork
EI 380 Shannon-London Heathrow
EI 381 London Heathrow-Shannon
EI 030 Belfast-London Heathrow
EI 031 London Heathrow-Belfast
EI 231 London Gatwick-Dublin
EI 232 Dublin-London Gatwick
Affected (Irish) Ryanair services:
FR669 Birmingham-Dublin
FR668 Dublin-Birmingham
Additional reporting: PA