Slang: Speed, Dexy's Midnight Runners, phet, meth, base, glass, uppers, whizz, billy, sulph, wake-up and crank paste.
Background: Speed is the most popular name for amphetamine, which is a chemical compound that acts as a central nervous system stimulant. Its chemical structure closely resembles the body's own chemical transmitter norepinephrine, which plays an important role in the fight-or-flight response to stress and excitement. There are three main pharmaceutical classes of amphetamine (the common brand names are in brackets): laevo or dl-amphetamine (Benzedrine), dextroamphetamine (Dexedrine) and methylamphetamine (Methedrine).
The latter is also known as crystal meth and, weight-for-weight, is the most potent of the three. The most common street speed is amphetamine sulphate, which contains equal amounts of laevo-amphetamine and dextroamphetamine.
Amphetamines comes as a grey, dirty-white or pinkish powder which is snorted, rubbed on the gums, dissolved in liquid for injection or drinking, or swallowed in pill form. A 'speedbomb' consists of speed wrapped in Rizlas, which is then swallowed. It's the most impure illegal drug available in the UK - it can be heavily cut with paracetamol, baby milk, talcum powder or other substances, so it's unlikely you'll know exactly what you're taking. Base speed - which is pinkish-grey and feels like putty - is purer.