A harbour has been closed to swimmers after "above normal" levels of E-coli were discovered in the water.
Visitors to the Dover site will not be able to enter the sea until further notice following the discovery during routine tests.
However, the Port of Dover, the organisation that runs the harbour, stresses that it has not received any reports of ill health.
A spokesman said: "We would like to inform our community that unfortunately water standards were not met following our routine tests.
"There have been above normal E-coli bacterial levels indicated in these samples.
"The health and safety of our customers and community is of the utmost importance to us and therefore we have taken these measures as a precaution. There are no reports of ill health."
The Port of Dover decided to close the landmark to anyone taking part in water-based activities after holding discussions with Dover District Council and the Environment Agency.
The authorities advised to keep it shut until the situation is better understood.
Further tests are due to take place today and tomorrow - the results of which are expected to be revealed on Tuesday.
"We are working with external agencies in order to lift the restriction at the earliest opportunity," the spokesman added.
"Port of Dover would like to apologise for any inconvenience this may cause."