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3 Parts of Plant: Fruiting/Flowering Tops; Aerial Parts, Stalk; Seed (Non)viable

3 Parts of Plant: Fruiting/Flowering Tops; Aerial Parts, Stalk; Seed (Non)viable

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In UK law this anomaly could not be resolved simply by tabling a new statutory

‘Modification Order’ because the ‘Cannabis’ definition was contained within the

body of the MDA—unlike most other ‘dangerous drugs’ which were substances and

products described in the appended Schedule 2 which is accessible to amendment by

an ‘Affirmative Resolution’ in parliamentary debate. Accordingly, the definition in

the principal act, the MDA itself, had to be amended in respect of the cannabis

definition. This was conveniently achieved by inserting an additional section [s. 52]

among a variety of general amendments to the criminal law that were collated in the

Criminal Justice Act of 1977. Herbal cannabis, after excluding the resin, was thereby

redefined as—

“all the aerial parts, except the lignified stem and the non-viable seed, of any plant of the genus


Note that this new definition deliberately excluded the roots from control under the


This revision in the UK in 1977 was forced because previous attempts to control

herbal material other than flowering or fruiting parts, such as lower leaf and stalk,

could not necessarily rely on demonstrating to the Court the presence within the

herbal material of controlled ‘cannabinoids’ (see below, §1.7 for discussion of controls

on congeneric substances constituting the active principles of the herb). After a variety

of rulings in lower courts, the link between these other parts of the plant and the

‘cannabinoids’ controls was finally tested in a key judgment in the House of Lords.

Thus, in the case of R v Goodchild (1977–78), itself following two Crown Court

hearings and two Appeals, their Lordships ultimately ruled that leaves and stalk

which had been separated from the harvested plant did not constitute the separated

resin and nor were these other parts of the plant legally equivalent to those

cannabinoids naturally contained within them (which substances were listed in a

controlled drug category attracting a higher level of penalty—see §1.5 and §1.7 below).

1.4 Compendial Definitions

The British Pharmacopoeia 1914 edition was the last to provide a monograph for

cannabis; the ‘Characters’ and ‘Tests’ are described in §4.1. This monograph defined

“Cannabis Indica”, alias “Indian Hemp”, as the—

“dried flowering or fruiting tops of the pistillate plant Cannabis sativa Linn.”

and added “grown in India, from which the resin has not been removed”.

The British Pharmaceutical Codex 1949—the last BPC to contain a Cannabis

monograph—retained only the first part of the BP 1914 definition (i.e. no reference

to origin or to removing resin) but added “(Fam. Cannabinaceae)”. This edition of

the Codex also prescribed recipes for preparation of (alcoholic) Extract of Cannabis

and the appropriate dilution to make Tincture of Cannabis.

The Japanese Herbal Medicines Codex and the Chinese Pharmacopoeia have

current monographs for ‘hemp fruit’ and ‘Huo Ma Ren (i.e. marihuana) respectively:

see Đ4.1 later.

Copyright â 1998 OPA (Overseas Publishers Association) N.V. Published by license under the Harwood Academic Publishers imprint,

part of The Gordon and Breach Publishing Group.



1.5 Cannabis Oils

In the UK, the ‘Controlled Drugs’ listed in Schedule 2 to the MDA 1971 are subdivided

between ‘Parts’ I, II and III, respectively containing drugs of ‘class A’, ‘B’ and ‘C’,

largely following the classification in Schedules I–III in the UN Single Convention

1961; this distribution sought to strike a balance between the perceived degree of

social harm and the medicinal value of the substances. In Schedule 4 to the MDA,

direction is given for the prosecution and punishment of various relevant offences

(cf. §2 below) and a descending scale of penalties reflects the allocation of substances

between classes A, B and C. A fourth Part of MDA Schedule 2 provides legal definitions

for those entries in Parts I–III of Schedule 2 that do not admit exact chemical


‘Cannabinol derivatives’ are listed in Part I, i.e. are controlled as ‘class A’ drugs

and explicitly defined in Part IV (see full definition in §1.7). This definition carries

the exclusion “except where contained in cannabis or cannabis resin”. The latter

natural products were already listed in Part II and thus attracted the lower penalties

of class B drugs. Following the revised definition of ‘Cannabis’ in s. 52 of the Criminal

Law Act 1977, the herbal form of the drug thereafter legally subsumes “all aerial

parts” (except lignified stem and non-viable seeds) of the plant.

In the DDA 1965, following on the UN Single Convention 1961, ‘Any extract or

tincture of cannabis’ (as exemplified by, but not limited to, the alcoholic preparations

of the BP 1914 and BP Codex 1949) were listed in a subsequent clause in the schedule

containing ‘Cannabis’ and its resin. These named preparations were deliberately

omitted from Schedule 2 of the MDA 1971 and control of ‘extract’ or ‘tincture’

thereafter rested on a general reference to “preparations” (of the appropriate class of


The more or less concentrated ‘Cannabis oil’ is a solvent extract containing 20–

40% of the potent principal cannabinoid, tetrahydrocannabinol (THC), and just

occasionally, appreciably higher concentrations are detected (cf. Figure 2, later). If

judged by UK seizures, so-called hash oil exported from the ‘resin belt’ countries (i.e.

Indian subcontinent, Middle East, Morocco) often contains three or four times the

common local level (say, 5–15%) of THC in resin from that region; whereas liquid

cannabis preparations from the Caribbean and East Africa may represent tenfold

concentration of the much lower level (say, 1–3%) of THC in local herb. Some recent

seizures (King, 1997) of the oil appear to derive from extraction of intensively

cultivated herbal cannabis. Cannabis oil may be clandestinely prepared, from either

herbal or resin forms of cannabis, by extraction with ethyl or methyl alcohol in, for

instance, a large drum. The mixture is then filtered and the filtrate concentrated by

evaporation of solvent (e.g. in a pressure cooker); it may be purified by treatment

with petroleum ether.

Cannabis oil was for many years regarded in UK forensic practice as a preparation

of THC, a class A drug (see §1.7). However, if a lower potency oil, only comparable

in THC content with the Extract or Tincture of the BPC 1949, is supported by collateral

evidence of botanical origin, then ‘a preparation of a class B drug’ is a more appropriate

and equitable prosecution charge. If the solvent were entirely removed, the viscous

residual product might then be regarded as ‘purified cannabis resin’, because the

MDA 1971, also places the resin—defined in s. 37(1) as the separated resin, whether

Copyright © 1998 OPA (Overseas Publishers Association) N.V. Published by license under the Harwood Academic Publishers imprint,

part of The Gordon and Breach Publishing Group.



crude or purified—in ‘class B’. However, where forensic practice treated oily extract

of herbal Cannabis as a preparation of THC, then the higher penalties of class A

would apply. This situation was recognised as anomalous.

The main constituents of the oil are tetrahydrocannabinol (THC) and cannabinol

(CBN); but if made from resin, some cannabidiol (CBD) is also present. Accordingly,

identification of the presence of CBD permits assumption of a resin source, whence

in UK law the oil can be treated as ‘purified cannabis resin’ in ‘class B’. But in the

absence of CBD, or if a herbal source of the oil is otherwise proved or admitted, then

‘a preparation of THC’, not being Cannabis, predicates assignment as ‘class A’. Such

a decision was upheld in the case of R v Carter in Oxford Crown Court in December

1992, when the oil was not accepted as “a preparation of Cannabis”.

This discrimination in Britain was widely considered as unreasonable, especially

for low concentration ‘cannabirum’ extracts from the Caribbean, and various options

for changes in UK law were considered:

1. Add a new entity ‘Liquid cannabis’ to Part II [i.e. with class B] and add a new

definition to the list in Part IV [e.g. “a product which has been prepared from

cannabis or cannabis resin by solvent extraction”.]

2. Transfer cannabinol and cannabinol derivatives from Pt. I to Pt. II of Sch. 2 of MDA.

3. Amend Sch. 2 of the MDA as at 2. but maintain the distinction between

nontherapeutic and therapeutic Controlled Drugs through Sch. 1 and 2 of

subordinate Misuse of Drugs Regulations.

Option 2 was regarded as administratively tidier but it conflicted with the UN Single

Convention placement of cannabinoids in its Schedule I and cannabis products in

Schedule II. Subsequently, the UN recommended for [potential] medical usage reasons,

transferring pure THC {as one potent stereoisomer, under its US and WHO nonproprietary medicinal name ‘dronabinol’} from Sch. I to II. This isomer was a clear

candidate for the ‘medicinal’ Schedule, S2, of MD Regulations. Meanwhile, the Home

Office Forensic Science laboratories for some years anticipated option 1, by reporting

all ‘hash oil’ samples as ‘class B’ without distinction as to source, conveniently

regarding such specimens implicitly or explicitly as ‘purified cannabis resin’.

Firm recommendations to resolve this forensic anomaly were presented in 1996

by the Advisory Council on Misuse of Drugs but legal enactment has had to wait on

reference to the new parliament in 1997.

1.6 Smoking Residues

The partially pyrolysed residue in a pipe bowl or cigarette butt may still retain some

herbal features but is conveniently regarded as a crude specimen of ‘separated resin’.

Thus, the act of smoking has thermally ‘separated’ the resin from (herbal) cannabis.

The residue may be richer in THC than the original herb through thermal

decarboxylation of precursor acids [see next section] but the quantity (and quality!)

present will not usually be sufficient to constitute a dose for further smoking.

Morphological examination of uncarbonized material may provide forensic evidence

of herbal or intact resin but more frequently this distinction is blurred or inconclusive.

Nevertheless, the chemical evidence from the nature and proportion of cannabinoid

congeners may be capable of three interpretations:

Copyright © 1998 OPA (Overseas Publishers Association) N.V. Published by license under the Harwood Academic Publishers imprint,

part of The Gordon and Breach Publishing Group.



1. The process of distillation—in pipe (‘schaum’) or cigarette (‘joint’ or ‘reefer’)—

has produced purified cannabis resin, i.e. supporting a charge of simple possession

of a small quantity of a class B substance.

2. This constitutes evidence of having smoked, and therefore having had prior

possession of, a limited quantity of cannabis or resin or preparation thereof. As

pointed out by Phillips (1973), two lines may be accessible to defence of such a

charge: that the smoking implement at the material (prior) time had been in the

possession of some other identifiable person; or that the defendant had smoked

a preparation (such as Cannabis Tincture BPC) lawfully dispensed for him (cf.

Clarke and Robinson, 1970).

3. In the absence of any vegetative matter, the cannabinoid residue might point to

prior possession of a small quantity of cannabinol derivatives: but as discussed

in the previous Section, this leads to anomalous case law and potentially

inequitable penalties.

1.7 Natural Cannabinoids, Including C3 and Cl Analogues

At least 70 terpenoid phenols and acids have been reported to be isolated from

Cannabis. The origin and nature of these congeneric substances have been discussed

in Chapter 3. For convenience of discussion of structural variation of the natural

congeners (discussed in this Section), the synthetic homologues (in §1.8), their esters

(§1.9) and their respective stereochemistries (§1.10), their inter-relationships and

principal graphic formulae are illustrated in Table 2. Many of the congeneric substances

(originally identified as indicated in Table 2), such as cannabichromene, CBCh (with

ring-C open), cannabigerol, CBG (both rings B and C open) and cannbicyclol, CBCy

(cyclised to a fourth ring), and their various methyl ethers and carboxylic precursors,

are of insufficient psychoactivity to warrant international control as potential drugs

of abuse.

In the UK the first specific control of the cannabinoid natural constituents

cannabinol (CBN; Table 2, I: R=pentyl) and its tetrahydro derivatives, including the

most potent stereoisomer, delta9-trans-THC (Table 2, IIa), was their explicit listing as

psychotropic substances in 1970 in an addition to the schedule of drugs controlled

by the Drugs Prevention of Misuse Act (DPMA) 1964, thereby anticipating UN

proposals in the UN Psychotropic Substances Convention 1971, discussed in §1.8.

The distinction in seriousness of criminal offence between cannabinoid substances

and herbal specimens of cannabis was heightened by the MDA 1971, which placed

‘cannabinol and cannabinol derivatives’ in class A (the highest penalty class) but

listed cannabis and its resin (whether crude or purified) in class B, in harmony with

the UN classification. A range of hydrogenated ‘cannabinol derivatives’ was defined

in Part IV of Schedule 2 to MDA as—

“the following substances, except where contained in cannabis or cannabis resin, the

tetrahydro derivatives of cannabinol and 3-alkyl homologues of cannabinol or of its tetrahydro


This definition comprehensively subsumed not only all tetrahydro (structural) isomers

[see below for the US DAPCA 1970 legislation on this point], of which the delta9

Copyright © 1998 OPA (Overseas Publishers Association) N.V. Published by license under the Harwood Academic Publishers imprint,

part of The Gordon and Breach Publishing Group.



(alias delta1) and delta8 (alias delta6(1)) (cf. Table 2, IIIa) are the more common, whereas

other isomers, such as Adams and Baker’s (1940) synthetic delta3, 4 (Table 2, IIIb), are

curiosities; but it also extends to homologous sidechain derivatives. Thus, replacing

the 3-pentyl group by alkyl groups with more than 5 carbon atoms thereby brings

into control the synthetic 3-alkyl homologues of CBN and THC (see §1.8).

Table 2 Cannabinoid congeners and structurally related dibenzopyrans and chromenols

Copyright © 1998 OPA (Overseas Publishers Association) N.V. Published by license under the Harwood Academic Publishers imprint,

part of The Gordon and Breach Publishing Group.

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