Young Adam Rooney pricked his finger on the needle while rummaging for loose change in the pouch behind the driver's seat.

The 12-year-old had been celebrating his mum's birthday when the accident happened. The taxi, from Harrogate's Central Radio Cars was off duty and being driven by the boy's uncle, who has worked at the firm for 14 years.

Adam and his mum Sharon now face a nervous three month wait for final tests to reveal whether the youngster has contracted Hepatitis B from the three-inch syringe.

While the needle is believed to have originated in Harrogate, Central owner Kevin O'Boyle said it was the first time in 42 years he had dealt with a problem like this.

The incident took place on June 24 in Liverpool, where Adam lives with his mum.

The youngster was immediately rushed to Alder Hey children's hospital for blood tests, where doctors confirmed he did not have AIDS or HIV.

Mrs Rooney said she still feels "sick to the stomach" every time she thinks about the syringe and she described waiting for the results of the AIDS test as one of the most terrifying moments of her life.

Mrs Rooney said: "I was just so shocked. That syringe could have had animal blood, rat poison, anything inside it. It is just sickening - to pull a prank like this is so horrible.

"We have had a terrifying week and every time I think about it I feel sick. It is very frightening for us all."

Following the latest visit to the hospital yesterday, Mrs Rooney was told Adam needs a fresh blood test in six weeks, and another in three months.

Only then can Hepatitis B be ruled out. In the meantime, Adam will need regular injections in case he has contracted the virus.

The incident is now being investigated by officers from North Yorkshire Police.

A police spokesman said: "Enquiries are ongoing to determine the full circumstances surrounding the incident. At this early stage it is still unclear whether or not a criminal offence has been committed."

Central taxis owner Kevin O'Boyle said: "If a customer is going to go to the lengths of hiding a syringe in a pocket, I can not see it being practical for the driver to check everywhere to see if something has been left.

"To look in every nook and cranny, in practice, is not going to happen."

ashley.marshall@ypn.co.uk