An investigation is under way after a council roadsweeper was seen emptying onto a slipway near Morecambe Bay.
A member of the public said he'd spotted the council vehicle tipping its liquid contents onto the slipway near Morecambe Sailing Club race office on the Promenade, on Sunday at around 7.45am.
Passerby John Haydock, who saw the incident, reported it to the council and also posted a photo of the vehicle on Facebook asking for an explanation.
Lancaster City Council confirmed to Beyond Radio that it was their staff operating the vehicle.
A council spokesperson thanked Mr Haydock, said the practice was "not acceptable" and they would be taking "appropriate action".
Mr Haydock posted on Sunday: "Council vehicle emptying the liquid contents onto a public slipway at Morecambe Sailing Club, opposite the town hall.
"Can anyone enlighten me?"
Councillor Joanne Ainscough, Lancaster City Council cabinet member for environmental services, replied to Mr Haydock on Facebook later on Sunday.
Councillor Ainscough said she'd had a response from the council's chief officer for Public Realm.
This said: "I can confirm it is one of the city council's vehicles, however the reason for their actions is unclear.
"This sweeper will have been cleaning of the Promenade only at this time of the morning, the current assumption is given the weather, the operative is looking to drain the excess water content.
"Any detritus would be dropped at White Lund Depot.
"It will be picked up and thoroughly investigated as to the exact reason."
Councillor Ainscough also posted to Mr Haydock: "Thank you for bringing it to people's attention. We can only improve things if we are made aware of them."
A Lancaster City Council spokesperson said on Monday: "We would like to thank the member of the public for bringing this to our attention and to reassure people that this practice is not acceptable.
"The matter is currently being investigated and appropriate action will be taken to ensure it does not happen again."
UPDATE - In July the council told us: "The matter has been investigated and is now closed. Appropriate action has been taken to ensure it does not happen again."
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