Samms drove his car at the warden, the court heard

Dennis Samms, 42, of Kingfisher Close, Manchester, spat in the warden's face and drove at him after he tried to issue a fine, city magistrates heard.

NCP, which operates the city's traffic wardens, introduced DNA testing kits to protect staff from assaults.

Samms pleaded guilty to assault after his saliva was tested with a "spit kit" and is due to be sentenced on Thursday.

Tax disc

He is believed to be the first driver in the country to be convicted on evidence gained in this way.

The court heard Samms started spitting at the warden when he was told his tax disc was out of date.

The warden then had to take cover behind a parking meter and took a photo of Mr Samms on his camera phone.

He then had to wait four minutes before another warden came to his aid with a "spit testing" kit.

No one should have to put up with being spat at just for doing their job Tim Cowen, NCP

District Judge Paul Richardson said: "In these days of HIV and Aids spitting in this fashion takes on a hugely more serious aspect.

"You did no physical injury but the incident must have frightened your victim most severely - I'm not ruling out a custodial sentence."

HIV is not transmissible via spitting.

The kits were introduced at NCP's depot in Ardwick last May.

About 80 members of staff at the depot have been trained to use them.

Tim Cowen, a spokesman for NCP, said: "This guy has been trapped by his DNA and that is conclusive proof.

"This was introduced to protect parking attendants and has proved effective.

"One assault is one too many and no one should have to put up with being spat at just for doing their job."

A spokeswoman for Greater Manchester Police said DNA swabs taken from parking attendants are sent for analysis and can lead to a prosecution for common assault.