People are being urged not to join a trespass swim at two flooded quarry workings where four people have drowned.

It comes after it emerged campaigners have been encouraging wild swimming at Bawsey Country Park, near King's Lynn, whose two lakes have claimed four lives over the last decade.

An event has been organised for this Sunday at the park, whose owners have banned swimming for safety reasons.

Sandra Squire, cabinet member for the environment at West Norfolk council, said: "We are asking anyone who has seen this event advertised not to take part.

"While we would not want to prevent people from taking part in wild swimming, we must discourage people from doing it in a location with a history of drownings.

"Anyone new to the area or not familiar with its history may not be fully aware of the risks. It is the combined opinion of the council and Bawsey Country Park that this is not a safe place to swim."

The organiser of Sunday’s event has put together a web page with an assessment of ‘risks and myths’ about the site but the council says that some of the information on this assessment is wrong, including a statement that there is no evidence for risks beyond the usual risks of swimming outdoors in cold and deep water.

Bawsey Country Park emphasised that it has very clear rules and swimming is not allowed. The rules are displayed on signs across the site in text and pictorial form. 

A spokesman for the park said: "We do not wish to paint Bawsey Country Park as dangerous as it is not dangerous if people respect the rules.

"We are concerned that if this activity is promoted to the public as going to occur at Bawsey, or frankly any inland water be it the River Thames or Loch Lomond, that more people may think that they would like to participate and break the rules thus increasing the chances of tragedy."