Vehicles will display a newly-designed poster which reinforces the message that those who assault ambulance staff will be prosecuted.

The Tees, East and North Yorkshire Ambulance Service NHS Trust says the move is in response to a rise in attacks nationally.

Recent incidents have seen crews attacked with knives and bitten.

Tony Wearmouth, controls assurance manager with the trust, said: "Since April this year, there have been 14 physical assaults against our ambulance crews, 26 assaults which didn't result in an injury, and 43 cases of verbal abuse and intimidation.

Tackle aggression

"This is not acceptable and we hope these posters will be a stern reminder."

Unison union official Glen Gears said: "Violence against ambulance staff is completely unacceptable.

"It appears to be on the increase and we are encouraged that the trust is taking steps to address the problem.

"We hope this campaign will help to tackle the aggression that our ambulance staff face on a sometimes daily basis."

Mr Wearmouth added: "A number of successful prosecutions against people who have attacked ambulance crews have been made resulting in prison sentences, fines, tagging and ASBOs.