Medical tests on his hair in early 2008 also revealed Dr Chahal had cocaine in his system, the hearing was told, but he denies ever taking the Class A drug. He told investigators the only recreational drug he had ever taken was cannabis at university.

Mr Sephton added: “He was not being honest when speaking to health assessors . . . it wasn't simply inaccurate, but was also dishonest.”

Dr Chahal left Ormskirk hospital on July 31, 2007, in his position as senior house officer, but continued to work as a locum there until August.

He went on to work at Alder Hey for a matter of weeks, before he was suspended over the Entonox allegations.

Steve Ryan, medical director at Alder Hey, said: “He had been in employment with us for just a few weeks when Southport and Ormskirk alerted us.

“He was suspended while an investigation was carried out, and then dismissed.

“Patient safety was not at risk at any time, and all the incidents relate to Ormskirk.”

A spokesman for Southport and Ormskirk Hospital Trust said: “No children were affected by this incident.

“He has not been employed at this trust since.”

Doctors carrying out the tests on Dr Chahal also concluded he was suffering from an undisclosed medical condition.

The case continues.