A landslide warning has been issued by the Met Office, as continued heavy downpours sparked fears of unstable cliff faces.
Boxing Day walkers were urged to take extra care in "dangerous conditions" with flooding set to worsen across parts of England and Wales today.
The Met Office has issued the warning following advice from the British Geological Survey .
Forecasters said coastal areas in southwest England are in particular danger of collapsing cliff edges, but stressed that all areas with heavy rain are at risk.
A spokesman for the Met Office said: "We have had such heavy and persistent rain fall over the last few days and weeks and that there is a danger of landslides and rockfall along the coast, even on coastal paths.
"We are advising Boxing Day walkers in the southwest of England to take particular care in these dangerous conditions, especially those not familiar with the area.
"Do not get too close to the cliff edge or walk under the cliff face along the beach and remember that coastal paths could be impacted too."
Many coastal paths have been closed over the last few weeks along the South West and train services have been disrupted by small coastal landslides.
There have been several landslide tragedies involving walkers in recent years. Last summer, Charlotte Blackman was buried by rocks while walking with her family on the Dorset coast .
Weather experts said up to 15mm of rain fell across southwest England and south Wales, with up to 20mm expected again today.
Sky weather presenter Sarah Pennock said there would be more heavy rainfall over some areas of the UK .
She said: "The main event today is a band of rain already spreading into southwestern Ireland and Scotland.
"This will dump up to an inch in places, will fall on already saturated ground and will exacerbate the risk of further flooding."
The Environment Agency has 117 flood warnings in place , which urge residents to take immediate action against expected flooding.
A further 228 less severe flood alerts have been issued across most of England and Wales.
The Scottish Environment Protection Agency has removed all its warnings, with lighter showers expected only through the southwest of the country.
Around 470 properties have flooded since Wednesday, while Floodline revealed it has received 18,000 calls during the recent wet weather.
The worst affected areas have been southwest England and stretches along the south coast from Cornwall to Kent, along with Wales and northern Scotland.