Adam Blackburn, 16, has Asperger's syndrome and difficulties with his coordination. He is also a keen swimmer and he cannot remember a time when he did not swim. He is the only member of his local swimming club with a disability, but a coach there saw his potential and has spent time developing his talent.

Adam takes his training seriously now and swims for two hours or more each week. His father, Craig Blackburn, would like his son to have the opportunity to swim and compete more. Competitive swimming in the regions is administered by British Swimming and the Amateur Swimming Association (ASA), and these bodies follow the classifications set down by the International Paralympic Committee (IPC) for swimmers with disabilities.

But Adam does not fit into any of their classifications. He was recently tested for the IPC S14 category, which caters for swimmers with learning difficulties, but just failed to meet the required score on the IQ test.

Up until last year, Adam would have been able to compete under a category that was unique to Britain – S17. It was introduced for swimmers with Developmental Coordination Disorder (DCD) – or dyspraxia – a condition that is not recognised by the IPC's classification system.

The abandonment of the S17 category has left Adam and many young people like him with no opportunities to progress from local competitions to regional, let alone national or international swimming meets. Yet S17 swimmers used to comprise 5-10% of entries at disability swimming events.

Gillian Hindle, a former disability classification coordinator, doesn't understand why the S17 category has ended. "I thought the legacy of the Paralympics was inclusion," she says, "and this seems to me to be exclusion."

British Swimming and the ASA's reason for no longer supporting S17 is simple: dyspraxia is not recognised abroad. "As the national governing body for swimming, the ASA and British Swimming mirror the international processes and procedures to ensure compliance with the IPC," a spokeswoman for the ASA says. "Unfortunately, swimmers with dyspraxia are not recognised internationally as being eligible for competitive para-swimming."

However, the ASA is keen to point out that swimmers who once qualified as S17 are now free to enter the same competitions as able-bodied swimmers. "We still support and continue to support all disabled swimmers at grassroots level who do not meet the eligibility criteria set out by IPC for para-swimming, with opportunities being provided through mainstream competitions," the spokeswoman adds.

But Craig Blackburn is scathing about the decision to withdraw S17. "I think it is an utter disgrace," he says, and is less than enthusiastic about his son competing against other children without disabilities. At one such event, he noticed that Adam was being picked on by other teenage boys because he was different.

"The children have to compete against other non-disabled children," he says, "but because of their disability, they don't train as well, they don't learn as well, so therefore they are going to be slower.

"They can't compete with the able-bodied because of their disability, but they can't compete with the disabled because of the type of their disability. They are disabled, but as far as the ASA is concerned, they are not."

Christopher Robertson is a lecturer in inclusive and special education at the University of Birmingham's school of education. He explains that someone affected by DCD cannot compete on equal terms with an able-bodied person.

"If someone is severely affected by dyspraxia," he says, "one would expect that it would cause major difficulties in terms of organisation and planning and perception – for example, being able to recognise distances when reaching out for something.

"It could impact on speed of movement, strength of movement, and all those things that we do on a day-to-day basis."

He believes that those with DCD should be given the opportunity to become involved in sports at all levels.

Mary Butler has been involved with disability swimming for over 30 years. She was a director of the English Federation of Disability Sport, and is now a East Midlands' regional swimming coordinator for disability sport events.

Butler is organising the region's disability swimming championships, due to take place in Leicester this weekend.

Against official British Swimming/ASA policy, she has included the S17 classification in her gala. An alternative "official" championship has been arranged for June, fully endorsed by British Swimming and the ASA, with no S17 category swimmers.

Some of the young swimmers at these events are competing for places in the Paralympic team for Rio 2016. Robertson accepts that, because it is a spectrum disorder, categorising dyspraxia in any meaningful and consistent way is fraught with difficulties. But the value in participation and competition for those concerned is worth the effort, he thinks.

"The way to think these things through is not to say 'How do we exclude?' but to ask 'What can we do to include?'", he says. "And if that is messy and awkward, and involves people falling out over things, then so be it."