Informants have always played a key role in policing. Contrary to what the public might think they are generally motivated by other things rather than monetary gain although payments to informants used to be entered in ‘red ink’ in CID officers diaries in the West Midlands. On the TV informants are commonly referred to as ‘grasses’. In Birmingham and the Midlands they were called ‘sarbut’s’. The origin of the word is not clear but may be linked to the phrase ‘saboteur’. Nowadays there is a ‘posh’ word – ‘Human Intelligence Sources’. Whatever they are called they are without doubt the most cost-effective weapon in the armoury of crime investigators.