The FCDO said many parts of the country were experiencing adverse weather conditions.
It warned: “Some areas of Lisbon are flooded due to heavy rain, causing travel disruptions to trains and metro lines. Some major roads are closed.”
The Portuguese authorities have issued yellow and orange alerts for mainland Portugal, the Azores and Madeira. These are expected to remain in place until Friday (16 December).
Reuters said Lisbon’s mayor’s office had put the city on a "red" weather warning at around 06.30, urging people to stay home and avoid commuting to the capital.
Lisbon sits on the estuary of the River Tagus and reports said the river was in danger of bursting its banks.
