Subsequent inquiries have revealed that the drug, known as 'lilies', is likely to be the depressant quinalbarbiton (seconal), which may also be referred to as seggies, or seckies.

The drug is believed to be presented in the form of 50mg and 100mg orange-coloured capsules, marked with either F42 and F40.

Effects of the drug can last for three to six hours and the consequences could be fatal.

Symptoms include irritability, insomnia, fainting, nausea and delirium or even life-threatening seizures.

A police spokesman said: "Police are concerned about the circulation and consumption of these drugs, which could result in serious illness or even death if misused. Even a low dosage of the drug could result in fatal consequences."

Anyone with any information is asked to call police immediately on 03456 043 043.

Meanwhile, police executing a warrant found low-level drugs, not lilies, at a property in Amble on Tuesday morning.