More than 25 children have been stung by jellyfish in one day on a Kent beach, which are believed to have been enticed inland by the warmer shallow waters.

Volunteer rescue crews described yesterday as 'exceptionally busy' as thousands of people descended on Folkestone beach.

Spectators gathered to watch the Folkestone and Hythe RAF 100 air show and take part in an annual sandcastle competition among other pre-planned events on Sunday.

But according to a coastal rescue charity, unsuspecting swimmers who had been soaking up the festivities such as the Red Arrows and Battle of Britain flyovers found themselves a bit too close to the sea creatures, following a suggested increase in sightings in the last few weeks.

Now Folkestone Rescue, which works alongside Dover Coastguard, the RNLI and NCI Folkestone, are concerned the issue may not die down if the hot weather continues.

Russell Reilly, communications manager, said: "Every couple of metres we could see the jellyfish.

"There was definitely an increase over the weekend in terms of what we dealt with.

"Its always the warmer water that brings them in.

"It's all to do with the water temperature."

He continued: "We are not trying to scare anyone. We're just trying to make people aware."

'Every couple of metres we could see the jellyfish. There was definitely an increase over the weekend in terms of what we dealt with.' - Russell Reilly, Folkestone Rescue

The group told people on site yesterday to keep an eye out and be careful following an initial jellyfish warning two weeks ago on their blog.

They had suggested swimmers wear full-length wetsuits and other protective gear.

In an updated statement, the charity said: "Yesterday was an exceptionally busy day with the Sandcastle Competition, Battle of Britain Memorial Flight and the Red Arrows and other events taking place meant a large number of people were enjoying the sun, sea and sights at Sunny Sands.

"Over the course of the day, our crew treated around 25 to 30 children who had received compass jellyfish stings of varying severity while swimming.

"Most of the injuries were relatively minor with no further treatment needed after the jellyfish stings had been neutralised by applying vinegar."

The volunteer organisation, which covers the coast between Sandgate and Dover, had 10 volunteer crew members working on the seafront yesterday in anticipation of the crowds.

Scores of visitors in Folkestone, Hythe and Romney Marsh have taken to social media to report sightings of the sea creatures in recent weeks.

However, the Maritime and Coastguard Agency said last week it had not been made aware of any increase in cases.

While in most cases local species only carry a mild sting, they can be dangerous in larger groups. There have also been recent reports of lion’s mane jellyfish in Hythe - a specie considered to have the most powerful sting in Britain.

The charity's logistics manager Chris Lightwing said: "If you have been stung by a jellyfish, you should leave the water immediately and keep still.

"Any remaining tentacles should be removed with tweezers whilst wearing gloves.

"If you have difficulty breathing after being stung, you should seek medical attention immediately by calling 999."

They also warned that jellyfish can 'give a nasty sting' and should never be handled.

The crew also assisted with other medical incidents on the day, including a woman with chest pains, a child with a weever fish sting and an injured man pulled from the sea near coastal defence rocks.