Unfortunately there is some National data that suggests autistic adults are more likely to be unemployed or underemployed, despite having the skill sets and expertise to excel in the workplace. However under the Equality Act 2010 ASC is recognised as a disability and as a result a person with ASC can be provided with certain rights and protections under the law. For example employers must make reasonable adjustments to allow the person to perform their best work and protect them from discrimination, harassment and victimisation.
It is up to the individual whether or not they choose to tell their employer they have ASC. Any person has the right to keep this information private. Some people are concerned that they might face workplace discrimination if they tell their employer that they have ASC. However, telling the employer can help with accessing the support and workplace adjustments that are needed to support the individual to enjoy and be successful in their chosen career.
Autismwales.org have put together a useful resource booklet that helps to explains more about employment rights: