Emergency services rescued dozens of people off the coast of Suffolk this afternoon after swimmers taking part in a race got into difficulties.

Around 130 people were taking part in the 1.2km Southwold Pier to Pub Swim when the drama happened.

It is understood the race was a little late starting and by the time competitors entered the water conditions had deteriorated with the sea choppy and currents strengthening.

After more than an hour of the race, many competitors were very tired and the decision was taken for the RNLI teams present to start pulling people out of the water.

Coastguards scrambled all available emergency services.

It is understood three people were missing, but later two of these were accounted for – one airlifted to safety by an RAF Sea King helicopter – and treated for hypothermia. A third person was still not found but may have come ashore and not reported to organisers.

One eye-witness said: “There were about 130 people signed up to do the swim. This was the second year – last year it went really well and everyone got round the course.’

“This year, it seemed like there was a delayed start and very quickly it looked like people were having problems. One of the guys said the wind had changed.

“One of my friends who took part said it was like swimming on a treadmill. She spent an hour in the water and ended up north of where she had started. She was supposed to be swimming south. She, and lots of other people, were rescued by the lifeboat.

“I was told that only about 20 people out of the original 130 actually finished the course.

“Lots were rescued by the lifeboat, and others just gave up and swam back to shore. We heard that some people were missing, but we hoped that this was because they had swum to shore and simply gone home without telling anyone.’’

The swim – organised by Active Outdoor Events in cooperation with Adnams of Southwold – was due to start at noon from north of the pier and end at the Lord Nelson Pub.

Active Outdoor Sport runs a wide range of events, including duathlons, running, triathlons, aquathlons and open water swim events, for novices to elite athletes.

In its instructions for competitors ahead of the swim said a risk assessment had been carried out and would be reviewed on the morning of the swim.

The instructions said: “Any necessary amendments to the swim from conditions on the day, including postponement, will be implemented accordingly.

“In the event that conditions make the swim as planned unsafe then the event will be postponed to an alternative date or will be conducted over a shorter distance starting to the south of the pier.

“Swimmer safety is our primary concern and ensuring that the safety measures in place can operate in the prevailing conditions are key to ensuring this.”

Kayakers from the Waveney & District Canoe Club were due to help guide swimmers on the course with rescue support being provided by the RNLI beach lifeguard service.

Swimmers took part in a mass start north of the pier, running from the beach into the sea and heading out to the first turn buoy.

They were then due to swim past the end of the pier and turn landwards at the final buoy to reach the shore.