Dublin put emergency plans into place last night after severe flooding suspended rail services, closed roads, caused flight delays and left businesses and homes deluged with water.
The torrential rain equated to a month's rainfall in just one day.
An off-duty policeman is missing and feared dead after a river broke its banks in Country Wicklow. He was thought to have been helping people on the upper stretches of the River Liffey.
The city's main shopping centre had to be evacuated, while the heavy rain caused flight delays in and out of Dublin Airport, and forced the closure of two motorways.
Rail services on the east coast were affected, with the Belfast to Dubkin Enterprise link being cancelled, according to Travel Mole.
Irish weather service, Met Eireann, has issued a severe weather warning for large areas of Ulster and east Leinster.
Other parts of the UK have also been affected by torrential rain, with flood alerts being issued for coastal and river areas in Cornwall, Devon, Swansea, Pembrokshire, and Carmarthenshire.
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