Mike Ferguson was transporting an organ for transplant

Mike Ferguson, whose case is due in court on Wednesday, said transplant patients had offered to pay his costs and any fine because of their outrage he was facing legal action.

The West Yorkshire Metropolitan Ambulance Service driver was travelling from St James's Hospital in Leeds to Addenbrooke's Hospital in Cambridge in the early hours of 16 January when he was allegedly caught speeding at 104mph on the A1.

The road had a 70mph limit and Mr Ferguson, who was delivering a liver for a transplant operation, was charged with speeding by Lincolnshire Police.

The 56-year-old was in an official vehicle with blue lights flashing.

Online petition

On Tuesday, Mr Ferguson addressed delegates at the annual conference of his union, the GMB, which is campaigning to have the case dropped.

"I have had thousands of letters, e-mails, postcards and verbal messages of support from all over the world, including Australia, Spain and Gibraltar," he said.

"People have said they cannot understand why someone in an emergency service is being prosecuted for doing his job."

The GMB said an online petition had received 1,500 messages of support for Mr Ferguson in the past few days.

The union has written to Home Secretary David Blunkett and Health Secretary Alan Milburn urging them to intervene.