A charge of speeding against a Bradford ambulance driver who was travelling at more than 100mph while delivering a liver for a transplant patient has been dropped.

Mike Ferguson, was due to go on trial next week after being charged earlier this year. He was stopped by police as he drove down the A1 at 104 mph in Lincolnshire in January delivering a donor liver from St James's Hospital, Leeds, to Addenbrooke's Hospital, Cambridge.

But Mr Ferguson's union, the GMB, revealed today that the Crown Prosecution Service had decided that the prosecution was not in the public interest.

Mr Ferguson, 56, who faced losing his job if he had been prosecuted, said he was "overjoyed" at the decision. "It's wonderful news," he said. "I knew late last night that we wouldn't have to appear in Court on Monday but I didn't know the reason. Apparently it is not in the public interest to pursue this."

Mr Ferguson, of Birkenshaw, said he and his union would continue to campaign for a law change to prevent similar prosecutions.

"We're still going to push for a change in the law, or a review," he said. "It is really a nonsense to say people can't break the speed limit when they are trying to save a life.

"I don't agree with speeding - I see the result of it all too often in this job - but I think that in circumstances like this there is sometimes a necessary risk, unfortunately."

Gary Baker, the union's regional officer, said: "The GMB is very pleased that the CPS has finally seen sense and decided not to prosecute.

"The only good thing to come out of this absurd situation is in highlighting that the law needs to be updated to keep up with medical advances like transplants."

Mr Baker added the union would continue its campaign to get the Government to review the law to avoid similar cases happening in the future.

Earlier this week, Mr Ferguson travelled to Downing Street to hand in a petition signed by more than 18,000 people supporting his case.

Mr Ferguson has an unblemished employment record stretching back 36 years and has a clean driving licence.

Bob Williams, operations director for West Yorkshire Metropolitan Ambulance Service, said: "We are pleased that Mike Ferguson will now be able to continue his work without the threat of a court case hanging over him.

"We look forward to being able to continue to work as part of the UK human organ transportation programme."

John Durkin, the GMB's branch secretary for ambulance drivers, said he was "over the moon" that the case had been dropped.

"We can now get back to the business of saving lives. If Mike had been found guilty, the repercussions throughout the service would have been very damaging.

"We are all trained to drive safely at high speed and we take our jobs very seriously.

"A few minutes make a big difference when you are in the business of saving lives."

Mr Ferguson's trial was due to be held at Grantham Magistrates' Court where the case is now expected to be formally dismissed on Monday.