The coastguard at Felixstowe has warned open-water dippers of the dangers of swimming in the Suffolk sea as water temperatures plunge.
With indoor swimming pools closed due to the coronavirus lockdown, people across the country have opted to swim the sea for exercise.
However, this has led to an increase in responses for the HM Coastguard service - with callouts for swimming-related incidents rising nearly 80% in a year.
Felixstowe Coastguard Rescue Team said on Facebook that cold water shock is a risk whenever temperatures reach below 15C.
The national average temperature across the UK waters is between 6-10C - with the mercury reaching just 6C in the sea off Felixstowe on Monday.
In response, the Felixstowe coastguard team has urged swimmers to take precautionary measures such as not entering the water alone, checking weather and forecast times and wearing a wetsuit with a brightly-coloured swimcap.
The Felixstowe team said on Facebook: "We are keen that the ever-growing number of swimmers and dippers are aware of the risks and know how to enjoy the activity safely and responsibly."
Last August, an emergency operation led by the coastguard was launched after two swimmers were believed to be in trouble in the water near Felixstowe Pier.
An Essex and Herts air ambulance landed in the nearby Langer Park as police and paramedics also joined the rescue effort, though the pair were later found safe and well.
One of the swimmers was qualified swimming coach Seamus Bennett, who said he goes into the water "every day" and insisted he was not in danger.
Mr Bennett, who is also a town councillor, has said sea swimming can help with mental health - but urged people to be prepared for the low temperatures.
He said: "Open-water swimming is increasing in popularity, partly because of pools being closed but also because it's free. It's there to boost people's mental health.
"I would urge people to take it easy - be organised so you don't go in on your own.
"Getting out of the water is sometimes the trickiest part. Do get changed very quickly.
"Unless you're very experienced, more than 10 minutes in the water is a challenge. Focus on your breathing and try not to focus on the cold."
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