Children are being diagnosed with attention deficit hyperactivity disorder and prescribed drugs in the same way that doctors performed unnecessary tonsillectomies 50 years ago, according to the creativity and education expert Sir Ken Robinson.

The number of children diagnosed with ADHD in the United States had been around 500,000 in the 1980s. Last year, that figure had grown to eight million, he said. The prescription of drugs for the condition was “pathologising a generation” and a “terrible mistake”, he said.

While he did not dispute the medical evidence that the condition of ADHD exists, he had difficulty believing it was as widespread as the numbers suggested. “I know from my experience that kids are being routinely medicated to get them to concentrate or become focused at exam time,” he said.

The use of drugs such as Adderall and Ritalin was shutting down the real personalities and creativity of some children. “You have to look at cases individually. I know some kids create difficulties and are disruptive - that was always true. Great teachers always knew how to handle them.

“One of the reasons it is more difficult for teachers to handle them now is that schools are in such a straitjacket to perform. If a tablet is available that will calm them down, then people will reach for it.”