Drugs: the crucial hours

Drugs experts today claimed delaying a test by 24 hours could make all the difference between a positive and negative result.

Here, toxicologist Professor John Henry describes how the body breaks down common drugs:

COCAINE: taken for recreational purposes. Stays in the body up to 48 hours. Professor Henry says: "If a footballer had taken an average line of coke, the body would break half of it down within two hours. "The liver would usually break the rest down within 24 hours, though it could still be detectable up to 48 hours later."

STEROIDS: taken to enhance sporting performance. Stay in the body up to a week. Professor Henry says: "Most steroids are taken orally and could be in the body for up to a week. "So-called 'depot steroids' are taken by injection and could last months, but these are less common. Detecting these drugs in urine can be quite difficult and requires sophisticated laboratory tests. "A delay of 24 hours could be useful, depending on exactly when the substances had been taken."

ECSTASY: taken for recreational purposes. Stays in the body at least 48 hours. Professor Henry says: "This drug will not be broken down by the body for at least 48 hours, possibly longer. A 24-hour delay could make all the difference."

CANNABIS: taken for recreational purposes. Stays in the body two to three days. Professor Henry says: "There is something of a myth that cannabis can be detected for weeks and months after it has been taken, but this would require very sophisticated tests indeed. "The substance would normally be detectable in urine for two to three days."