Isla Denholm was giving evidence at the fatal accident inquiry into the death of her 10-year-old son Darren at the Peffermill clinic in Craigmillar, Edinburgh, last October.

BBC Scotland's David Nisbet reports on the first day's evidence

Darren, from Armadale, in West Lothian, was taken to hospital but efforts to revive him failed.

Mrs Denholm said that no-one at any stage had explained the risks between local and general anaesthetic.

"A man, whom I presume to be the anaesthetist, came running out of the room and said to get an ambulance," she told the inquiry.

She said that at 4.20pm she saw an ambulance outside the clinic but did not see anyone leave it and come into the building.

Darren Denhom: Taken to hospital

"I went and asked what was going on and was told by a receptionist that a nurse would come and see me, but no-one came.

"By 4.30 I was shouting at them, 'Darren's my son, surely I have a right to speak to him'."

But when she approached the door of the surgery she said she heard a key clicking on the other side and was ushered away.

A paramedic then came to speak to her and asked her to go with him to a private room where he told her: "Mrs Denholm, Darren has gone into cardiac arrest.

"I said: 'Don't be so ridiculous he was only in to get a tooth out'. Then I started to scream because I realised he meant it.

"I ran downstairs to phone my husband but he could not understand me and the paramedic took the phone and explained the situation to him."

Isla Denholm: No explanation

Mrs Denholm was taken to the Royal Hospital for Sick Children, where Darren was, and was told by a doctor: "I'm so sorry, we have been trying for a long time but there's nothing we can do."

She added: "I asked if they could wait for my husband to come but they said Darren had been through enough."

The anaesthetist who treated Darren, John Evans-Appiah, told procurator fiscal Robert Shiels he had been a practising anaesthetist since 1976.

He was carrying out work for Poggo Anaesthetics of Kent and agreed he only received payment from the company when he used a general anaesthetic on a patient.

He said Darren was brought in as an emergency and acknowledged he had seen the consent form filled in and signed by Mrs Denholm and accepted it was unsigned and undated by anyone else.

BBC Scotland reporter Nigel Rosbon : "The incident happened last October..."

Mr Evans-Appiah said he asked about Darren's previous medical history and added: "Darren was very much afraid of needles. I promised Darren that I would give him gas instead of the jab."

He agreed an assessment involving testing blood pressure and pulse normally was carried out on patients before being given general anaesthetic but said this did not happen with Darren because of his anxiety.

Mr Shiels asked him about figures recorded on the form detailing Darren's blood pressure and asked if he had carried out the pre-operative assessment.

The anaesthetist said he had carried out the assessment but accepted he did not record Darren's blood pressure.

Mr Shiels asked: "Are you saying that these blood pressure figures are fiction?"

Mr Evans-Appiah: Quizzed about checks

Mr Evans-Appiah replied: "No. Yes. I cannot tell you the reason why this was not recorded."

After he had begun giving Darren the general anaesthetic, he walked around the boy and noticed he was moving, so he increased the gas concentration.

Mr Shiels asked if he formed any impression at this stage about Darren's breathing pattern and Mr Evans-Appiah replied: "Yes, I found that his breathing was shallow to the point that he might stop breathing."

Mr Evans-Appiah said he had failed the second part of an anaesthetics course which would have allowed him to specialise in that field.

Earlier, he told Mr Shiels he had learned after the incident that a local anaesthetic had been given to the boy by Norwegian dentist Hallgier Pedersen.

Anne Smith QC, counsel for the dead boy's parents, said tests on Darren after his death had shown the general anaesthetic and the local anaesthetic had reacted with each other to kill the child.

Mr Evans-Appiah said he did not think this would have caused Darren's death.