The event will take place at the National Aquatic Centre in Dublin ©Paralympics Ireland

A major test for the new classification system in Paralympic swimming will unfold when the European Championships open tomorrow in Dublin.

The World Para Swimming-organised event  is being billed as a "major step" in the development of the sport.

It follows the introduction of new classification rules and regulations in January.

A record 122 swimmers still require classification in the three days before the start of the competition.

The event will take place over seven days at the National Aquatic Centre in the Irish capital.

The revised rules are the product of "extensive work and research into how physical and intellectual impairments impact on an athlete’s ability to do the sport and perform each swimming stroke".

An athlete’s ability is assessed by a panel of at least two classifiers during an evaluation in which they undergo a series of water tests and exercises.

In some cases, an observational assessment of an athlete swimming during competition will be held to assess their ability in the water.

It is likely that some of these in-water assessments will take place during heats in the championships itself.

However, with a small number of events going straight to a final, it is "unavoidable that some observation assessments will need to take place when medals are at stake".

"If an athlete’s sport class is changed following the observation assessment, the result of the event they competed in will be amended accordingly," World Para Swimming said.

"Should an athlete be required to undergo a further evaluation following the observation assessment, then the results of the race will be unofficial until this process is complete."