A probe has been launched after athletes fell ill following the World Triathlon Championship series in Sunderland. 

The competition went ahead on Sunderland's Roker last weekend (July 29 and 30), despite "concerns" around water quality results for a test taken on July 26 by the Environment Agency as part of their regular testing of the local area.

The test results were published on Monday, July 31, after the AJ Bell 2023 World Championship Series event had taken place. 

Though these concerning results were taken outside of the Roker Pier arms and not in the body of water used for the swim, several athletes have reported illness to the organising body British Triathlon. 

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British Triathlon, UK Health Security Agency North East (UKHSA North East) and Sunderland Council are now investigating the cause of the illness, and have encouraged anyone feeling unwell to view online resources. 

In a statement, British Triathlon explained the testing protocol in the run-up to the event: "In line with the World Triathlon guidelines for hosting a World Triathlon Championship Series event, a series of water quality tests were undertaken in the build-up to the event including on Thursday 20 July and analysed in a United Kingdom Accreditation Service (UKAS) accredited laboratory.

"These results were received on Tuesday 25 July and passed the required standard to host the event. 

"Also in line with World Triathlon guidelines, a further test was conducted during the course of the event on Sunday 30 July and analysed in a UKAS-accredited laboratory. Indicative results were received on Wednesday 2 August and passed the required standard to host the event. 

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"Both of these tests were taken within the Roker Pier arms where the swim leg of AJ Bell 2023 World Triathlon Championship Series Sunderland took place.

"On Monday 31 July, data was published by the Environment Agency showing reduced water quality was detected on Wednesday 26 July in an area of Roker Beach outside of the pier arms and swim area of the event.

"Since Monday 31 July, British Triathlon has been working closely with Sunderland City Council and UK Health Security Agency to seek further information and investigate the cause of the illness."