Thousands of patients are waiting months for an autism diagnosis in Oxfordshire and two other counties.

New figures show that 1,500 additional patients with suspected autism in Buckinghamshire, Oxfordshire and Berkshire are waiting for a diagnosis this year.

It comes as waiting lists have expanded across England, with an autism charity warning the "diagnosis wait crisis" is taking a toll on patients' mental health, and called on the Government to "urgently fix this broken system".

In the NHS Buckinghamshire, Oxfordshire and Berkshire West Integrated Care Board area, 8,825 patients were waiting for an autism assessment, up from 7,380 last year.

Of these, 89 per cent (7,880) had a referral that had been open at least 13 weeks.

The NHS target is for every patient with a referral to receive a first appointment within 13 weeks.

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Just one per cent of the patients with an open referral for more than 13 weeks entering September in Buckinghamshire, Oxfordshire and Berkshire received a first appointment that month.

Tim Nicholls, assistant director of policy, research and strategy at the National Autistic Society, said the figures should be "a huge wake-up call to the Government to urgently fix this broken system which lets down autistic people and their families".

An NHS England spokesperson said: "While there remains high demand for autism assessments, we are seeing an improvement in the number of assessments completed.

"But we know there is more to do, which is why we have published new national guidance to help local partners to deliver high-quality autism assessment services and to manage the 161% increase in referrals over the last four years, while providing enhanced autism training for psychiatrists."