A council contractor is being investigated after “very dark” liquid was discharged across a seafront promenade.

There were fears the black spillage across the pathway at Minnis Bay in Birchington – seen seeping down to the beach below – could be harmful to residents or the environment.

Kent County Council (KCC) says its contractor Conway was responsible for the spillage, which happened when a vehicle released water from equipment into the gullies to check the drains were working correctly.

But the Environment Agency (EA) – responsible for any enforcement action – is investigating the incident.

Thanet’s shadow deputy leader and Birchington councillor George Kup says he was alerted to the liquid dumped on Sunday by a contractor via a Facebook post shared by a disgruntled resident.

“The liquid looked very dark in colour and at the time it was not clear what the liquid could be nor whether it was harmful to residents or the environment,” the Conservative said.

“We made Thanet District Council’s foreshore team aware of the situation and it has now made contact with the necessary people to get it cleared.”

Cllr Kup called for the matter to be investigated as he believes it “cannot be acceptable”.

“We are very lucky in Minnis Bay to have a Blue Flag Award mainly due to the hard work of the volunteers who spend their time clearing our beach from rubbish and keeping our beach tidy,” he added.

“We must all work together to ensure the beach we love is clean, tidy and accessible for all users and the actions we saw over the weekend do not help us in achieving that.

“We will be pushing for the clear-up of this liquid to be thorough and for answers to be found as to why it happened.”

The EA says it takes pollution of seas and rivers “seriously” and will take “appropriate enforcement action” where it finds illegal activity.

“TDC informed us about this incident and are making further enquiries on this matter,” a spokesman said.

A KCC spokesperson says the authority attended the site, began the clean-up and informed the drainage team of the incident after being alerted to the spillage on Sunday.

“The drainage team investigated the spillage and sent a contractor to clean up the area on Monday,” they said.

“This particular incident happened when the contractor released water from their equipment into the gullies to check the drains were working correctly, without realising that these particular gullies discharge across the promenade.

“The contractor has spoken to their workforce to reiterate the importance of leaving sites clean."

A TDC spokesperson says KCC is the responsible authority and – having been notified – completed the clean-up.

"The Environment Agency has been made aware and is the authority responsible for any enforcement relating to this type of incident,” they said.

“Thanet District Council will not be taking any enforcement action."