Hertfordshire Police have revealed there were 23 serious and fatal crashes involving drugs in the county last year.

The force is warning motorists not to drive while under the influence as it backs a national drug driving campaign starting today (Monday).

People on drugs are twice as likely to be involved in a crash and are five times more likely to kill someone, officers said.

They also warned that drugs stay in the system longer than alcohol, meaning motorists can test positive days later and are more likely to be caught.

Chief Inspector Stephen O’Keeffe, head of the tri-force roads policing unit, said: "Driving while under the influence of drugs is extremely dangerous.

"They affect people in a variety of ways, all of which impair the way you think, act and react.

"The consequences of this can be devastating when you are supposed to be in control of a moving vehicle."

He added that anyone who appears to be driving erracticly will be stopped by officers and if a drugs test is refused or returns positive they will take further action.

Penalties include a criminal record, a 12-month driving ban, an unlimited fine and a prison sentence.

"Drug driving is a serious crime that destroys lives," he continued. 

"If convicted you face a hefty fine as well as the possibility of a driving ban or prison time, not to mention the chance of losing your job.”

To report a drug driving incident call 101 or 999 in an emergency.

Anyone who takes drugs is encouraged to seek advice and support from the drug charity FRANK.