TOXIC substances such as glass and rat poison are being mixed in to drugs to make them heavier before they are sold on our streets.

Police say strychnine and pain-killers are among substances that have been added to drugs.

But one High Wycombe dad, who found his son with cannabis, said glass was also being added to the drug to make it heavier.

He said yesterday: "It's rubbish covered in poison. These dealers are trying to make a quick buck by putting poison in it, but someone will have to go and bury their child over this."

Detective Inspector Steve Williams, Bucks' lead officer in the current fight against drugs, said: "Drug dealers use all kinds of substances to bulk up their merchandise and make more money.

"I have seen lab reports for cocaine come back listing chalk and powdered pain-killers as ingredients."

The horrified High Wycombe dad said how he found his son had bought drugs laced with glass.

The father claimed yesterday that dealers were doing this to make a fast buck.

"They are adding this to it to make up the weight - people must be going to hospital over this," he said.

"My son smokes it and I have to accept the fact I can't stop him going out and buying it. But I have to make sure it won't kill him.

"I rubbed it in my fingers and it was like when you're eating an ice cream at the beach that has got sand on it. What is that doing to their lungs? These dealers are putting whatever they like into the cannabis and it's on the streets of Wycombe. Someone is going to die and it will be a young kid."

Police say the chemicals are added to cannabis resin to give users an extra buzz. Cannabis resin is a solid block of the drug, while herbal cannabis is chopped, dried leaves from the cannabis plant.

Sergeant Gordon Reilly said: "We have seen strychnine rat poison in blocks of cannabis resin. That has been mixed in with cannabis resin for quite a while. It comes in from abroad, added in from the manufacturers within the warehouse. It gives it an extra buzz."

Sgt Reilly added: "People must understand the dangers when taking what they think is a relatively harmless drug. In some situations the wrong mixture could be fatal."

* If you have information on contaminated drugs, contact police on 08458 505 505 or Crimestoppers anonymously on 0800 555 111.