Getting an autism diagnosis in the UK is still a two-tier system. An NHS assessment costs you nothing but the wait can run to years, while a private assessment is much faster and typically costs between about £800 and £2,500. For many adults the choice comes down to how long they can wait and what they can afford, not what they would prefer.
The three routes at a glance
| Route | Cost to you | Wait | Main catch |
|---|---|---|---|
| NHS | Free at the point of use | Reported at 3-7 years for adults, varying by area | The wait itself |
| Private | £800-£2,500 depending on clinician, location and how comprehensive it is | Usually 2-8 weeks | You pay up front |
| NHS Right to Choose (England) | Nothing, if your referral is funded | Depends on the provider | Availability and funding vary by area |
NHS route: free but long waits
An NHS autism assessment is free on the point of use. Waiting lists are the real barrier: most NHS services report waits of between 3 and 7 years for adults, and they differ a lot from one area to the next. For children, waits are somewhat shorter (typically 1-3 years) but still significant.
The pathway usually starts with a referral from your GP, followed by initial screening and then a full diagnostic evaluation by a specialist team. Quality varies by region. NICE's guidance on autism in adults (CG142) sets out what a good diagnostic assessment should involve, which is a useful yardstick for judging any provider.
Private assessment: speed at a cost
Private assessments cost roughly £800-£2,500. London practices typically charge £1,500-£2,500, while regional clinics may be £800-£1,200. Most are completed within 2-8 weeks. Private reports are commonly accepted by employers and universities.
Before you pay, check who is doing the assessment. Practitioner psychologists should be registered with the HCPC, and doctors with the GMC. Ask whether the assessment follows NICE guidance and whether the clinician has experience diagnosing adults, since presentation in adulthood, especially in women, can look different from the textbook picture.
Right to Choose: limited but growing
In England, the NHS "Right to Choose" policy allows your GP to refer you for an autism assessment with any provider that holds an NHS contract, including private clinics, with the NHS paying. It bypasses your local waiting list. It is an English arrangement: NHS Scotland, NHS Wales and Health and Social Care in Northern Ireland run their own pathways.
In practice it is patchy. The providers with NHS contracts are limited in number and can have their own queues. Funding is decided through your local Integrated Care Board (ICB), and some are more willing to pay than others. Some GPs are also unfamiliar with the process, so it can take persistence. If a referral goes through you pay nothing.
Hybrid approach
Many adults choose a private assessment (£1,500-£2,000) for a faster diagnosis, then use NHS support such as speech therapy or occupational therapy afterwards. That costs money up front but means a diagnosis within months instead of years. One caution: acceptance of a private diagnosis by NHS services can vary, so ask your GP or local service before you pay.
Do you need a diagnosis to get support?
Not always. Under the Equality Act 2010 in Great Britain, your employer's duty to make reasonable adjustments depends on how your condition affects you day to day, not on holding a particular piece of paper. A diagnosis makes the conversation simpler and gives you evidence, but the absence of one is not, in general, a legal bar.
The UK adult autism diagnosis guide walks through each step from screening to report, and what to expect at an autism assessment describes the appointments. If you are weighing up whether to seek a formal diagnosis at all, the case for and against self-diagnosis covers both sides.
Screening and clinical assessment
Many autistic adults have never been formally diagnosed. Free online screening tools exist, but none replace a clinical assessment. This page is general information, not medical advice, and your GP or a suitably registered clinician is the right person to talk to about whether to seek an assessment.