Philip and Kathryn Havard with their new son, Jack

Six-week-old Aaron Havard was having surgery for a stomach problem when the fatal error happened in April 2002.

Dr Robert Falconer, 45, was cleared of manslaughter through gross negligence at Swansea Crown Court on Tuesday.

Kathryn and Philip Havard said they had not yet decided whether to take legal action over their baby's death.

During the trial, the jury heard consultant anaesthetist Dr Falconer had injected two doses of air into a drip leading into Aaron's bloodstream instead of into his stomach to inflate it.

On realising the mistake, the court heard, he fought with the rest of the medical team for an hour - unsuccessfully - to try to save the baby's life.

Dr Falconer described his action during the operation at Singleton Hospital in Swansea as a "catastrophic mistake" and, giving evidence, repeated an apology to Mr and Mrs Havard in open court.

Dr Falconer, from Sketty in the city, was off work for three months after Aaron's death.

Baby Aaron was in hospital for a routine operation

The General Medical Council told the BBC News website on Wednesday they would "be looking at the outcome of the case to determine whether the doctor's fitness to practise should be questioned".

At present, Dr Falconer has full registration to practise in the UK and is on the specialist register for anaesthetics.

Mr and Mrs Havard, from Manselton in Swansea, said they were glad the truth of what had happened to Aaron had finally been heard in public.

But Mrs Havard, a nursery nurse, said: "[Dr Falconer] went back to work very quickly after the situation and we have been a bit miffed by that to be honest.

He was such a brave little boy going into that theatre Philip Havard

"If you are that devastated, you can't go back to work and I'll never understand that because I know that in my job I couldn't have gone back to work if anything serious happened."

Her husband added: "There is a bit of bitterness the way everything's happened.

"The way he went back to work, because I was off for four months and I still go to counselling.

"We're never going to get over this. It's a very difficult at the moment."

He paid tribute to his son, whom he called after the trial ended as "Mummy's little soldier and Daddy's little champ".

He added: "The three days before Aaron had his operation he was having so many injections and he was in so much pain, but he was so brave.

"He was such a brave little boy going into that theatre."

Aaron was the couple's first child, but they now have a second son, six-month-old Jack.