and arrest leading to a court appearance. In the latter case, we assume arbitrarily that the
additional preparatory work increases the average time to 12 constable-hours plus 4 sergeanthours.
For the formal cannabis warnings which have been in operation since 2004, May et al (2007) assume an average time of 80 minutes to carry out eight steps, including the stop-and-search, police checks, completing a stop-and-search form, inputting details to various information
systems and transferring the seizure to the property store. It appears that the 80 minutes time
was not increased to allow for involvement of two officers in the action. To allow for this, we have increased the assumed time to 140 minutes. We assume the same time for the use of a Penalty Notice for Disorder (PND), which involves on-the-spot imposition of a fine.
For the time required to deal with an arrest for supply offences, we are in the realms of
guesswork, since we have found no relevant evidence in the research literature. We assume that
all arrests for supply and production offences involve preparation for a possible court case and that, on average, the process involves costs equivalent to 24 hours of constables’ time, 12
sergeant-hours and 10 inspector hours. These figures should be seen as an arbitrary illustration only: they have been chosen to give a unit cost figure close to the Brand and Price (2000) estimate of over £3000 per case.
Table 5.1.2 gives the resulting unit cost estimates, which range from £150 for a warning or PND, to £3,420 for an arrest for a supply offence. Since these figures are so uncertain, we also provide
a judgemental high-low range for each unit cost, which we are confident will contain the true
figure.
Table 5.1.2 Assumed times and unit costs for police actions
Activity Cannabis possession: formal warning or PND Cannabis possession: arrest and caution Cannabis possession: arrest and preparation for court Cannabis supply or production: arrest and preparation for court
Illustrative calculation of police time 140 constable minutes 8 constable hours + 2 sergeant hours 12 constable hours + 4 sergeant hour
20 constable hours + 8 sergeant hours + 8 inspector hours
Unit cost (mid estimate) £150 £660
High-low range £100-200
£400-£1000
£1060
£700-£1,500
£3,420
£2,000-£4,800
Note: calculations rounded to the nearest £10.
Official statistics on the volumes of drugs offences dealt with in various ways lack some of the
detail we would like for analysis of drugs policy. In particular, the specific substance (or
substances) involved in a particular detected drug offence is not recorded in a proportion of cases, and published data are often aggregated within the three official drug classes, so that
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